[SPARK-11039][Documentation][Web UI] Document additional ui configurations
[SPARK-11039][Documentation][Web UI] Document additional ui configurations

Add documentation for configuration:
- spark.sql.ui.retainedExecutions
- spark.streaming.ui.retainedBatches

Author: Nick Pritchard <nicholas.pritchard@falkonry.com>

Closes #9052 from pnpritchard/SPARK-11039.

pronix/spark,aray/spark,Aegeaner/spark,shubhamchopra/spark,jianran/spark,milliman/spark,nchammas/spark,apache/spark,goldmedal/spark,SHASHANKB/spark,kimoonkim/spark,xflin/spark,aokolnychyi/spark,ptkool/spark,milliman/spark,wzhfy/spark,big-pegasus/spark,guoxiaolongzte/spark,markhamstra/spark,cin/spark,mahak/spark,apache-spark-on-k8s/spark,kevinyu98/spark,rednaxelafx/apache-spark,HyukjinKwon/spark,vinodkc/spark,jianran/spark,nchammas/spark,mdespriee/spark,SHASHANKB/spark,liyichao/spark,SHASHANKB/spark,icexelloss/spark,lvdongr/spark,WeichenXu123/spark,lxsmnv/spark,xuanyuanking/spark,goldmedal/spark,ajaysaini725/spark,jkbradley/spark,ueshin/apache-spark,HyukjinKwon/spark,gengliangwang/spark,SnappyDataInc/spark,szhem/spark,sureshthalamati/spark,kimoonkim/spark,holdenk/spark,akopich/spark,guoxiaolongzte/spark,WeichenXu123/spark,HyukjinKwon/spark,kissmetrics/spark,WeichenXu123/spark,rikima/spark,debugger87/spark,andrewor14/spark,zzcclp/spark,zero323/spark,JerryLead/spark,andrewor14/spark,ibm-research-ireland/sparkoscope,darionyaphet/spark,rekhajoshm/spark,darionyaphet/spark,kevinyu98/spark,apache-spark-on-k8s/spark,jrshust/spark,darionyaphet/spark,maropu/spark,xuanyuanking/spark,janewangfb/spark,ddna1021/spark,witgo/spark,metamx/spark,alunarbeach/spark,spark-test/spark,yanboliang/spark,brad-kaiser/spark,1haodian/spark,mzl9039/spark,eyalfa/spark,caneGuy/spark,mzl9039/spark,vinodkc/spark,gioenn/xSpark,patrick-nicholson/spark,narahari92/spark,esi-mineset/spark,xuanyuanking/spark,mdespriee/spark,maropu/spark,publicRoman/spark,kissmetrics/spark,dongjoon-hyun/spark,facaiy/spark,eyalfa/spark,kiszk/spark,stanzhai/spark,stanzhai/spark,caneGuy/spark,dongjoon-hyun/spark,shaneknapp/spark,nilsgrabbert/spark,ptkool/spark,aosagie/spark,nchammas/spark,ptkool/spark,tengpeng/spark,spark-test/spark,liutang123/spark,sachintyagi22/spark,kiszk/spark,highfei2011/spark,tejasapatil/spark,jiangxb1987/spark,szhem/spark,jrshust/spark,matthewfranglen/spark,maropu/spark,mzl9039/spark,cloud-fan/spark,MLnick/spark,darionyaphet/spark,milliman/spark,rikima/spark,tejasapatil/spark,stanzhai/spark,xflin/spark,cloud-fan/spark,gengliangwang/spark,dbtsai/spark,alunarbeach/spark,jiangxb1987/spark,adrian-ionescu/apache-spark,dongjoon-hyun/spark,BryanCutler/spark,andrewor14/spark,darionyaphet/spark,ericvandenbergfb/spark,ddna1021/spark,szhem/spark,eyalfa/spark,aray/spark,sureshthalamati/spark,zuotingbing/spark,aokolnychyi/spark,esi-mineset/spark,jlopezmalla/spark,michalsenkyr/spark,JoshRosen/spark,nilsgrabbert/spark,WindCanDie/spark,zhouyejoe/spark,techaddict/spark,caneGuy/spark,yanboliang/spark,dhruve/spark,rezasafi/spark,kissmetrics/spark,facaiy/spark,highfei2011/spark,goldmedal/spark,rezasafi/spark,Panos-Bletsos/spark-cost-model-optimizer,liutang123/spark,UndeadBaneGitHub/spark,Panos-Bletsos/spark-cost-model-optimizer,gengliangwang/spark,srowen/spark,SnappyDataInc/spark,hvanhovell/spark,caneGuy/spark,1haodian/spark,facaiy/spark,gengliangwang/spark,ibm-research-ireland/sparkoscope,hvanhovell/spark,skonto/spark,patrick-nicholson/spark,sahilTakiar/spark,tejasapatil/spark,ConeyLiu/spark,mzl9039/spark,rednaxelafx/apache-spark,saltstar/spark,publicRoman/spark,panfengfeng/spark,caneGuy/spark,ptkool/spark,actuaryzhang/spark,jkbradley/spark,ddna1021/spark,UndeadBaneGitHub/spark,markhamstra/spark,saturday-shi/spark,aray/spark,wangmiao1981/spark,akopich/spark,hhbyyh/spark,highfei2011/spark,adrian-ionescu/apache-spark,poffuomo/spark,wangmiao1981/spark,hvanhovell/spark,lxsmnv/spark,HyukjinKwon/spark,ueshin/apache-spark,loneknightpy/spark,ibm-research-ireland/sparkoscope,skonto/spark,bOOm-X/spark,dhruve/spark,sahilTakiar/spark,ioana-delaney/spark,mzl9039/spark,michalsenkyr/spark,map222/spark,liyichao/spark,Aegeaner/spark,ioana-delaney/spark,JoshRosen/spark,witgo/spark,alunarbeach/spark,someorz/spark,patrick-nicholson/spark,1haodian/spark,ioana-delaney/spark,kimoonkim/spark,wangyum/spark,publicRoman/spark,esi-mineset/spark,saltstar/spark,gengliangwang/spark,patrick-nicholson/spark,liutang123/spark,bravo-zhang/spark,bdrillard/spark,techaddict/spark,janewangfb/spark,brad-kaiser/spark,SnappyDataInc/spark,wangyum/spark,zuotingbing/spark,WeichenXu123/spark,poffuomo/spark,alunarbeach/spark,mahak/spark,panfengfeng/spark,sureshthalamati/spark,srowen/spark,cloud-fan/spark,kevinyu98/spark,loneknightpy/spark,Panos-Bletsos/spark-cost-model-optimizer,huang1900/spark,guoxiaolongzte/spark,ddna1021/spark,shubhamchopra/spark,pronix/spark,ibm-research-ireland/sparkoscope,debugger87/spark,minixalpha/spark,rednaxelafx/apache-spark,holdenk/spark,highfei2011/spark,byakuinss/spark,ahnqirage/spark,zzcclp/spark,kevinyu98/spark,1haodian/spark,skonto/spark,apache/spark,rezasafi/spark,tengpeng/spark,stanzhai/spark,nlalevee/spark,Aegeaner/spark,guoxiaolongzte/spark,maropu/spark,WindCanDie/spark,metamx/spark,bdrillard/spark,shuangshuangwang/spark,jlopezmalla/spark,minixalpha/spark,aosagie/spark,ptkool/spark,ptkool/spark,hvanhovell/spark,HyukjinKwon/spark,bdrillard/spark,techaddict/spark,sachintyagi22/spark,pgandhi999/spark,tejasapatil/spark,kiszk/spark,szhem/spark,rekhajoshm/spark,shaneknapp/spark,minixalpha/spark,aosagie/spark,cin/spark,jlopezmalla/spark,dbtsai/spark,kiszk/spark,sachintyagi22/spark,sureshthalamati/spark,yanboliang/spark,haowu80s/spark,byakuinss/spark,apache/spark,maropu/spark,hvanhovell/spark,saltstar/spark,kissmetrics/spark,huang1900/spark,adrian-ionescu/apache-spark,rezasafi/spark,cin/spark,map222/spark,kimoonkim/spark,SnappyDataInc/spark,panfengfeng/spark,dhruve/spark,nchammas/spark,taroplus/spark,jrshust/spark,Panos-Bletsos/spark-cost-model-optimizer,shuangshuangwang/spark,mdespriee/spark,sachintyagi22/spark,narahari92/spark,ioana-delaney/spark,jkbradley/spark,byakuinss/spark,eyalfa/spark,saturday-shi/spark,someorz/spark,aray/spark,zhouyejoe/spark,pronix/spark,tejasapatil/spark,jiangxb1987/spark,apache/spark,patrick-nicholson/spark,taroplus/spark,liyichao/spark,shaneknapp/spark,ron8hu/spark,mahak/spark,jrshust/spark,ajaysaini725/spark,joseph-torres/spark,debugger87/spark,chuckchen/spark,chuckchen/spark,cin/spark,setjet/spark,kissmetrics/spark,bdrillard/spark,yanboliang/spark,haowu80s/spark,shuangshuangwang/spark,zhouyejoe/spark,jianran/spark,nlalevee/spark,cloud-fan/spark,saturday-shi/spark,nchammas/spark,ron8hu/spark,ueshin/apache-spark,eyalfa/spark,1haodian/spark,1haodian/spark,andrewor14/spark,spark-test/spark,bdrillard/spark,aosagie/spark,pgandhi999/spark,nilsgrabbert/spark,mzl9039/spark,panfengfeng/spark,shaneknapp/spark,zzcclp/spark,nilsgrabbert/spark,aokolnychyi/spark,akopich/spark,SHASHANKB/spark,bOOm-X/spark,patrick-nicholson/spark,shuangshuangwang/spark,goldmedal/spark,szhem/spark,zero323/spark,poffuomo/spark,cloud-fan/spark,MLnick/spark,liyichao/spark,ron8hu/spark,JoshRosen/spark,saltstar/spark,poffuomo/spark,esi-mineset/spark,sureshthalamati/spark,zzcclp/spark,apache-spark-on-k8s/spark,loneknightpy/spark,actuaryzhang/spark,SnappyDataInc/spark,rekhajoshm/spark,ddna1021/spark,wangyum/spark,bravo-zhang/spark,rikima/spark,spark-test/spark,adrian-ionescu/apache-spark,sahilTakiar/spark,kiszk/spark,byakuinss/spark,tengpeng/spark,kissmetrics/spark,chuckchen/spark,vinodkc/spark,lxsmnv/spark,xflin/spark,narahari92/spark,brad-kaiser/spark,milliman/spark,ahnqirage/spark,big-pegasus/spark,dhruve/spark,spark-test/spark,kevinyu98/spark,witgo/spark,kevinyu98/spark,wzhfy/spark,taroplus/spark,ConeyLiu/spark,pgandhi999/spark,Aegeaner/spark,mike0sv/spark,pronix/spark,ericvandenbergfb/spark,zero323/spark,esi-mineset/spark,zhouyejoe/spark,michalsenkyr/spark,witgo/spark,techaddict/spark,LantaoJin/spark,saltstar/spark,haowu80s/spark,actuaryzhang/spark,saturday-shi/spark,markhamstra/spark,jkbradley/spark,hhbyyh/spark,akopich/spark,UndeadBaneGitHub/spark,byakuinss/spark,markhamstra/spark,wangmiao1981/spark,someorz/spark,rezasafi/spark,saltstar/spark,lvdongr/spark,loneknightpy/spark,mdespriee/spark,wangmiao1981/spark,BryanCutler/spark,sureshthalamati/spark,joseph-torres/spark,eyalfa/spark,aray/spark,liutang123/spark,jrshust/spark,jianran/spark,markhamstra/spark,mzl9039/spark,nlalevee/spark,WeichenXu123/spark,jiangxb1987/spark,markhamstra/spark,joseph-torres/spark,nlalevee/spark,mike0sv/spark,JerryLead/spark,pronix/spark,UndeadBaneGitHub/spark,actuaryzhang/spark,cin/spark,gioenn/xSpark,vinodkc/spark,esi-mineset/spark,huang1900/spark,UndeadBaneGitHub/spark,Aegeaner/spark,map222/spark,janewangfb/spark,SHASHANKB/spark,JoshRosen/spark,jianran/spark,jlopezmalla/spark,wangyum/spark,tejasapatil/spark,lxsmnv/spark,setjet/spark,poffuomo/spark,ron8hu/spark,jianran/spark,pgandhi999/spark,shubhamchopra/spark,JerryLead/spark,xflin/spark,joseph-torres/spark,sahilTakiar/spark,tengpeng/spark,tejasapatil/spark,sahilTakiar/spark,kimoonkim/spark,highfei2011/spark,holdenk/spark,apache/spark,rikima/spark,janewangfb/spark,milliman/spark,dbtsai/spark,vinodkc/spark,jlopezmalla/spark,liyichao/spark,guoxiaolongzte/spark,UndeadBaneGitHub/spark,map222/spark,zero323/spark,yanboliang/spark,xuanyuanking/spark,Panos-Bletsos/spark-cost-model-optimizer,patrick-nicholson/spark,LantaoJin/spark,lvdongr/spark,darionyaphet/spark,jlopezmalla/spark,setjet/spark,rikima/spark,narahari92/spark,rekhajoshm/spark,loneknightpy/spark,srowen/spark,JoshRosen/spark,saturday-shi/spark,goldmedal/spark,panfengfeng/spark,mahak/spark,jiangxb1987/spark,lxsmnv/spark,setjet/spark,byakuinss/spark,ericvandenbergfb/spark,liutang123/spark,maropu/spark,rikima/spark,facaiy/spark,nlalevee/spark,ConeyLiu/spark,ron8hu/spark,haowu80s/spark,shubhamchopra/spark,techaddict/spark,SnappyDataInc/spark,apache-spark-on-k8s/spark,aokolnychyi/spark,lvdongr/spark,WindCanDie/spark,zuotingbing/spark,MLnick/spark,hvanhovell/spark,bOOm-X/spark,goldmedal/spark,ahnqirage/spark,skonto/spark,gengliangwang/spark,SnappyDataInc/spark,jianran/spark,kiszk/spark,apache/spark,big-pegasus/spark,rednaxelafx/apache-spark,saltstar/spark,actuaryzhang/spark,LantaoJin/spark,ueshin/apache-spark,tengpeng/spark,bdrillard/spark,janewangfb/spark,LantaoJin/spark,big-pegasus/spark,SHASHANKB/spark,janewangfb/spark,minixalpha/spark,wzhfy/spark,mdespriee/spark,esi-mineset/spark,zzcclp/spark,ptkool/spark,andrewor14/spark,map222/spark,WeichenXu123/spark,yanboliang/spark,WindCanDie/spark,MLnick/spark,markhamstra/spark,zhouyejoe/spark,big-pegasus/spark,wzhfy/spark,shubhamchopra/spark,ahnqirage/spark,taroplus/spark,tengpeng/spark,liutang123/spark,tengpeng/spark,icexelloss/spark,facaiy/spark,cin/spark,bdrillard/spark,bOOm-X/spark,aray/spark,dongjoon-hyun/spark,setjet/spark,michalsenkyr/spark,narahari92/spark,debugger87/spark,jlopezmalla/spark,wangmiao1981/spark,gioenn/xSpark,saturday-shi/spark,ueshin/apache-spark,rednaxelafx/apache-spark,zhouyejoe/spark,liyichao/spark,shuangshuangwang/spark,nlalevee/spark,hhbyyh/spark,zhouyejoe/spark,icexelloss/spark,LantaoJin/spark,yanboliang/spark,JerryLead/spark,minixalpha/spark,someorz/spark,nchammas/spark,jrshust/spark,loneknightpy/spark,akopich/spark,alunarbeach/spark,hhbyyh/spark,map222/spark,ibm-research-ireland/sparkoscope,MLnick/spark,icexelloss/spark,ConeyLiu/spark,MLnick/spark,caneGuy/spark,srowen/spark,andrewor14/spark,dongjoon-hyun/spark,shaneknapp/spark,ahnqirage/spark,ConeyLiu/spark,rezasafi/spark,wzhfy/spark,joseph-torres/spark,pgandhi999/spark,setjet/spark,skonto/spark,sahilTakiar/spark,zero323/spark,szhem/spark,bravo-zhang/spark,bOOm-X/spark,liutang123/spark,ddna1021/spark,gioenn/xSpark,facaiy/spark,minixalpha/spark,highfei2011/spark,gioenn/xSpark,jkbradley/spark,BryanCutler/spark,sachintyagi22/spark,someorz/spark,metamx/spark,wangmiao1981/spark,metamx/spark,lvdongr/spark,michalsenkyr/spark,WindCanDie/spark,wangyum/spark,JerryLead/spark,nchammas/spark,xuanyuanking/spark,mike0sv/spark,MLnick/spark,zuotingbing/spark,map222/spark,zero323/spark,adrian-ionescu/apache-spark,ibm-research-ireland/sparkoscope,JoshRosen/spark,witgo/spark,wzhfy/spark,xflin/spark,sachintyagi22/spark,publicRoman/spark,ioana-delaney/spark,lxsmnv/spark,dhruve/spark,ueshin/apache-spark,gioenn/xSpark,icexelloss/spark,kissmetrics/spark,apache-spark-on-k8s/spark,highfei2011/spark,kevinyu98/spark,mahak/spark,debugger87/spark,dongjoon-hyun/spark,wangmiao1981/spark,goldmedal/spark,joseph-torres/spark,xflin/spark,spark-test/spark,sachintyagi22/spark,metamx/spark,Aegeaner/spark,huang1900/spark,Panos-Bletsos/spark-cost-model-optimizer,facaiy/spark,xuanyuanking/spark,someorz/spark,sahilTakiar/spark,vinodkc/spark,SHASHANKB/spark,LantaoJin/spark,ericvandenbergfb/spark,milliman/spark,holdenk/spark,huang1900/spark,mahak/spark,actuaryzhang/spark,xflin/spark,cloud-fan/spark,caneGuy/spark,lxsmnv/spark,hhbyyh/spark,joseph-torres/spark,haowu80s/spark,dbtsai/spark,stanzhai/spark,mike0sv/spark,ioana-delaney/spark,ericvandenbergfb/spark,bravo-zhang/spark,wangyum/spark,andrewor14/spark,kiszk/spark,techaddict/spark,rednaxelafx/apache-spark,eyalfa/spark,huang1900/spark,apache-spark-on-k8s/spark,haowu80s/spark,UndeadBaneGitHub/spark,nilsgrabbert/spark,nlalevee/spark,szhem/spark,chuckchen/spark,apache/spark,witgo/spark,bravo-zhang/spark,wangyum/spark,gengliangwang/spark,gioenn/xSpark,rekhajoshm/spark,guoxiaolongzte/spark,shuangshuangwang/spark,srowen/spark,skonto/spark,poffuomo/spark,ueshin/apache-spark,narahari92/spark,aokolnychyi/spark,ddna1021/spark,ericvandenbergfb/spark,ron8hu/spark,akopich/spark,cloud-fan/spark,nilsgrabbert/spark,mdespriee/spark,liyichao/spark,JerryLead/spark,zuotingbing/spark,rednaxelafx/apache-spark,mahak/spark,vinodkc/spark,ahnqirage/spark,stanzhai/spark,poffuomo/spark,srowen/spark,aosagie/spark,jkbradley/spark,srowen/spark,BryanCutler/spark,chuckchen/spark,rezasafi/spark,byakuinss/spark,dongjoon-hyun/spark,jiangxb1987/spark,holdenk/spark,dbtsai/spark,Panos-Bletsos/spark-cost-model-optimizer,JoshRosen/spark,panfengfeng/spark,ron8hu/spark,alunarbeach/spark,minixalpha/spark,darionyaphet/spark,xuanyuanking/spark,actuaryzhang/spark,hhbyyh/spark,ConeyLiu/spark,BryanCutler/spark,JerryLead/spark,debugger87/spark,HyukjinKwon/spark,bOOm-X/spark,maropu/spark,LantaoJin/spark,pgandhi999/spark,lvdongr/spark,someorz/spark,guoxiaolongzte/spark,kimoonkim/spark,brad-kaiser/spark,chuckchen/spark,shuangshuangwang/spark,HyukjinKwon/spark,taroplus/spark,mike0sv/spark,shaneknapp/spark,publicRoman/spark,lvdongr/spark,dhruve/spark,zuotingbing/spark,1haodian/spark,zzcclp/spark,dbtsai/spark,Aegeaner/spark,debugger87/spark,rikima/spark,huang1900/spark,adrian-ionescu/apache-spark,icexelloss/spark,skonto/spark,panfengfeng/spark,ConeyLiu/spark,shubhamchopra/spark,aray/spark,WindCanDie/spark,brad-kaiser/spark,spark-test/spark,ajaysaini725/spark,chuckchen/spark,witgo/spark,rekhajoshm/spark,shaneknapp/spark,adrian-ionescu/apache-spark,kimoonkim/spark,janewangfb/spark,WindCanDie/spark,dhruve/spark,big-pegasus/spark,ericvandenbergfb/spark,hhbyyh/spark,mdespriee/spark,ajaysaini725/spark,bravo-zhang/spark,metamx/spark,jrshust/spark,stanzhai/spark,narahari92/spark,mike0sv/spark,ibm-research-ireland/sparkoscope,icexelloss/spark,michalsenkyr/spark,sureshthalamati/spark,aokolnychyi/spark,ajaysaini725/spark,bOOm-X/spark,jkbradley/spark,BryanCutler/spark,michalsenkyr/spark,metamx/spark,ajaysaini725/spark,bravo-zhang/spark,jiangxb1987/spark,holdenk/spark,milliman/spark,brad-kaiser/spark,hvanhovell/spark,techaddict/spark,nilsgrabbert/spark,mike0sv/spark,saturday-shi/spark,loneknightpy/spark,taroplus/spark,apache-spark-on-k8s/spark,publicRoman/spark,cin/spark,dbtsai/spark,big-pegasus/spark,publicRoman/spark,ioana-delaney/spark,ajaysaini725/spark,ahnqirage/spark,zzcclp/spark,BryanCutler/spark,setjet/spark,brad-kaiser/spark,akopich/spark,wzhfy/spark,rekhajoshm/spark,holdenk/spark,zero323/spark,taroplus/spark,alunarbeach/spark,aosagie/spark,pgandhi999/spark,pronix/spark,WeichenXu123/spark,shubhamchopra/spark,aokolnychyi/spark,zuotingbing/spark,aosagie/spark