[SPARK-22428][DOC] Add spark application garbage collector configurat…
[SPARK-22428][DOC] Add spark application garbage collector configurat…

## What changes were proposed in this pull request?

The spark properties for configuring the ContextCleaner are not documented in the official documentation at https://spark.apache.org/docs/latest/configuration.html#available-properties.

This PR adds the doc.

## How was this patch tested?

Manual.

```
cd docs
jekyll build
open _site/configuration.html
```

Author: gaborgsomogyi <gabor.g.somogyi@gmail.com>

Closes #19826 from gaborgsomogyi/SPARK-22428.

rekhajoshm/spark,lvdongr/spark,zuotingbing/spark,facaiy/spark,caneGuy/spark,darionyaphet/spark,szhem/spark,spark-test/spark,joseph-torres/spark,cloud-fan/spark,LantaoJin/spark,ddna1021/spark,techaddict/spark,jkbradley/spark,ptkool/spark,sureshthalamati/spark,bdrillard/spark,zero323/spark,tengpeng/spark,witgo/spark,ConeyLiu/spark,Aegeaner/spark,guoxiaolongzte/spark,caneGuy/spark,lxsmnv/spark,hvanhovell/spark,dbtsai/spark,shuangshuangwang/spark,ConeyLiu/spark,hvanhovell/spark,HyukjinKwon/spark,maropu/spark,Aegeaner/spark,WeichenXu123/spark,ptkool/spark,rezasafi/spark,esi-mineset/spark,bdrillard/spark,zero323/spark,WindCanDie/spark,zzcclp/spark,jiangxb1987/spark,kevinyu98/spark,taroplus/spark,zero323/spark,rikima/spark,hhbyyh/spark,xuanyuanking/spark,szhem/spark,cloud-fan/spark,milliman/spark,ahnqirage/spark,LantaoJin/spark,holdenk/spark,brad-kaiser/spark,nchammas/spark,brad-kaiser/spark,shuangshuangwang/spark,ahnqirage/spark,actuaryzhang/spark,debugger87/spark,srowen/spark,wangyum/spark,nlalevee/spark,witgo/spark,guoxiaolongzte/spark,rikima/spark,mahak/spark,caneGuy/spark,mdespriee/spark,sureshthalamati/spark,maropu/spark,nchammas/spark,milliman/spark,techaddict/spark,pgandhi999/spark,bdrillard/spark,BryanCutler/spark,zero323/spark,zhouyejoe/spark,holdenk/spark,hhbyyh/spark,holdenk/spark,spark-test/spark,rednaxelafx/apache-spark,HyukjinKwon/spark,markhamstra/spark,taroplus/spark,sahilTakiar/spark,ahnqirage/spark,lxsmnv/spark,wzhfy/spark,LantaoJin/spark,kiszk/spark,guoxiaolongzte/spark,apache/spark,michalsenkyr/spark,WeichenXu123/spark,wangyum/spark,spark-test/spark,zzcclp/spark,Aegeaner/spark,jiangxb1987/spark,cloud-fan/spark,dbtsai/spark,aosagie/spark,ConeyLiu/spark,lvdongr/spark,WeichenXu123/spark,bravo-zhang/spark,shaneknapp/spark,ron8hu/spark,goldmedal/spark,wangyum/spark,actuaryzhang/spark,kevinyu98/spark,mahak/spark,rednaxelafx/apache-spark,bravo-zhang/spark,ioana-delaney/spark,wzhfy/spark,wzhfy/spark,apache/spark,nlalevee/spark,HyukjinKwon/spark,nlalevee/spark,hvanhovell/spark,esi-mineset/spark,markhamstra/spark,sureshthalamati/spark,vinodkc/spark,jkbradley/spark,nchammas/spark,rezasafi/spark,ptkool/spark,goldmedal/spark,rekhajoshm/spark,szhem/spark,maropu/spark,JoshRosen/spark,ron8hu/spark,tengpeng/spark,HyukjinKwon/spark,tengpeng/spark,lvdongr/spark,ueshin/apache-spark,michalsenkyr/spark,goldmedal/spark,pgandhi999/spark,dbtsai/spark,wangmiao1981/spark,rezasafi/spark,ioana-delaney/spark,dongjoon-hyun/spark,sureshthalamati/spark,jiangxb1987/spark,ioana-delaney/spark,zzcclp/spark,szhem/spark,lxsmnv/spark,wangmiao1981/spark,goldmedal/spark,ptkool/spark,debugger87/spark,ron8hu/spark,rezasafi/spark,xuanyuanking/spark,saltstar/spark,hvanhovell/spark,skonto/spark,joseph-torres/spark,ioana-delaney/spark,rezasafi/spark,maropu/spark,nchammas/spark,spark-test/spark,gengliangwang/spark,gengliangwang/spark,jkbradley/spark,dongjoon-hyun/spark,srowen/spark,ueshin/apache-spark,lxsmnv/spark,markhamstra/spark,zhouyejoe/spark,ddna1021/spark,dbtsai/spark,ericvandenbergfb/spark,icexelloss/spark,tejasapatil/spark,wangmiao1981/spark,highfei2011/spark,rednaxelafx/apache-spark,facaiy/spark,tejasapatil/spark,zhouyejoe/spark,eyalfa/spark,zuotingbing/spark,mdespriee/spark,rednaxelafx/apache-spark,ueshin/apache-spark,witgo/spark,maropu/spark,zuotingbing/spark,actuaryzhang/spark,maropu/spark,facaiy/spark,BryanCutler/spark,taroplus/spark,saltstar/spark,dongjoon-hyun/spark,rikima/spark,bravo-zhang/spark,lvdongr/spark,ptkool/spark,WeichenXu123/spark,witgo/spark,BryanCutler/spark,cloud-fan/spark,tejasapatil/spark,skonto/spark,dbtsai/spark,BryanCutler/spark,kiszk/spark,WindCanDie/spark,rikima/spark,xuanyuanking/spark,facaiy/spark,saltstar/spark,Aegeaner/spark,Aegeaner/spark,dongjoon-hyun/spark,debugger87/spark,vinodkc/spark,maropu/spark,facaiy/spark,goldmedal/spark,gengliangwang/spark,ericvandenbergfb/spark,brad-kaiser/spark,techaddict/spark,dbtsai/spark,rednaxelafx/apache-spark,yanboliang/spark,debugger87/spark,zhouyejoe/spark,holdenk/spark,mdespriee/spark,hvanhovell/spark,hhbyyh/spark,brad-kaiser/spark,ddna1021/spark,debugger87/spark,HyukjinKwon/spark,caneGuy/spark,xuanyuanking/spark,facaiy/spark,icexelloss/spark,chuckchen/spark,zero323/spark,witgo/spark,wzhfy/spark,tengpeng/spark,highfei2011/spark,ddna1021/spark,lvdongr/spark,pgandhi999/spark,chuckchen/spark,mahak/spark,WindCanDie/spark,shaneknapp/spark,darionyaphet/spark,facaiy/spark,zzcclp/spark,kiszk/spark,tengpeng/spark,zzcclp/spark,markhamstra/spark,ericvandenbergfb/spark,skonto/spark,JoshRosen/spark,vinodkc/spark,wangmiao1981/spark,wangmiao1981/spark,shuangshuangwang/spark,LantaoJin/spark,kiszk/spark,techaddict/spark,zuotingbing/spark,shaneknapp/spark,kevinyu98/spark,nlalevee/spark,holdenk/spark,ron8hu/spark,ron8hu/spark,WeichenXu123/spark,milliman/spark,mdespriee/spark,guoxiaolongzte/spark,wzhfy/spark,lxsmnv/spark,caneGuy/spark,hvanhovell/spark,dbtsai/spark,eyalfa/spark,wangmiao1981/spark,rezasafi/spark,jiangxb1987/spark,ioana-delaney/spark,michalsenkyr/spark,BryanCutler/spar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