[MESOS] expand coarse-grained mode docs
[MESOS] expand coarse-grained mode docs

## What changes were proposed in this pull request?

docs

## How was this patch tested?

viewed the docs in github

Author: Michael Gummelt <mgummelt@mesosphere.io>

Closes #14059 from mgummelt/coarse-grained.

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