[SPARK-22112][PYSPARK] Supports RDD of strings as input in spark.read.csv in PySpark
[SPARK-22112][PYSPARK] Supports RDD of strings as input in spark.read.csv in PySpark

## What changes were proposed in this pull request?
We added a method to the scala API for creating a `DataFrame` from `DataSet[String]` storing CSV in [SPARK-15463](https://issues.apache.org/jira/browse/SPARK-15463) but PySpark doesn't have `Dataset` to support this feature. Therfore, I add an API to create a `DataFrame` from `RDD[String]` storing csv and it's also consistent with PySpark's `spark.read.json`.

For example as below
```
>>> rdd = sc.textFile('python/test_support/sql/ages.csv')
>>> df2 = spark.read.csv(rdd)
>>> df2.dtypes
[('_c0', 'string'), ('_c1', 'string')]
```
## How was this patch tested?
add unit test cases.

Author: goldmedal <liugs963@gmail.com>

Closes #19339 from goldmedal/SPARK-22112.

ioana-delaney/spark,jiangxb1987/spark,minixalpha/spark,highfei2011/spark,vinodkc/spark,nlalevee/spark,michalsenkyr/spark,kevinyu98/spark,rekhajoshm/spark,apache/spark,cin/spark,szhem/spark,holdenk/spark,debugger87/spark,zero323/spark,apache/spark,gengliangwang/spark,saltstar/spark,aosagie/spark,vinodkc/spark,ConeyLiu/spark,joseph-torres/spark,1haodian/spark,adrian-ionescu/apache-spark,debugger87/spark,shaneknapp/spark,rikima/spark,kiszk/spark,bdrillard/spark,ahnqirage/spark,milliman/spark,wangmiao1981/spark,yanboliang/spark,hvanhovell/spark,wangmiao1981/spark,chuckchen/spark,apache/spark,sahilTakiar/spark,sureshthalamati/spark,gengliangwang/spark,taroplus/spark,mdespriee/spark,michalsenkyr/spark,saltstar/spark,aosagie/spark,actuaryzhang/spark,JoshRosen/spark,wangyum/spark,spark-test/spark,holdenk/spark,bravo-zhang/spark,1haodian/spark,nchammas/spark,wangmiao1981/spark,1haodian/spark,kiszk/spark,techaddict/spark,xuanyuanking/spark,milliman/spark,BryanCutler/spark,skonto/spark,rekhajoshm/spark,szhem/spark,icexelloss/spark,witgo/spark,dbtsai/spark,goldmedal/spark,wangyum/spark,milliman/spark,rednaxelafx/apache-spark,minixalpha/spark,LantaoJin/spark,highfei2011/spark,hvanhovell/spark,techaddict/spark,rikima/spark,lvdongr/spark,ueshin/apache-spark,zuotingbing/spark,hhbyyh/spark,kevinyu98/spark,cin/spark,rikima/spark,ron8hu/spark,shaneknapp/spark,pgandhi999/spark,shaneknapp/spark,icexelloss/spark,rezasafi/spark,nlalevee/spark,nchammas/spark,pgandhi999/spark,1haodian/spark,jkbradley/spark,actuaryzhang/spark,shuangshuangwang/spark,srowen/spark,mdespriee/spark,joseph-torres/spark,highfei2011/spark,aray/spark,kevinyu98/spark,esi-mineset/spark,joseph-torres/spark,facaiy/spark,srowen/spark,darionyaphet/spark,debugger87/spark,zhouyejoe/spark,shubhamchopra/spark,vinodkc/spark,highfei2011/spark,mahak/spark,wangmiao1981/spark,cloud-fan/spark,shaneknapp/spark,witgo/spark,goldmedal/spark,tejasapatil/spark,akopich/spark,ueshin/apache-spark,sureshthalamati/spark,szhem/spark,lvdongr/spark,debugger87/spark,LantaoJin/spark,WeichenXu123/spark,chuckchen/spark,cloud-fan/spark,hhbyyh/spark,goldmedal/spark,kiszk/spark,hhbyyh/spark,adrian-ionescu/apache-spark,cloud-fan/spark,lvdongr/spark,BryanCutler/spark,nchammas/spark,xuanyuanking/spark,aosagie/spark,mdespriee/spark,HyukjinKwon/spark,sahilTakiar/spark,kiszk/spark,WeichenXu123/spark,bravo-zhang/spark,nchammas/spark,aray/spark,aray/spark,ueshin/apache-spark,srowen/spark,kevinyu98/spark,ericvandenbergfb/spark,maropu/spark,zero323/spark,caneGuy/spark,zzcclp/spark,wzhfy/spark,actuaryzhang/spark,zzcclp/spark,shuangshuangwang/spark,milliman/spark,vinodkc/spark,shaneknapp/spark,rezasafi/spark,tengpeng/spark,akopich/spark,skonto/spark,LantaoJin/spark,zero323/spark,szhem/spark,WeichenXu123/spark,WindCanDie/spark,chuckchen/spark,Aegeaner/spark,spark-test/spark,techaddict/spark,bravo-zhang/spark,ConeyLiu/spark,markhamstra/spark,eyalfa/spark,mahak/spark,taroplus/spark,rednaxelafx/apache-spark,icexelloss/spark,rednaxelafx/apache-spark,nlalevee/spark,mdespriee/spark,tengpeng/spark,maropu/spark,ConeyLiu/spark,yanboliang/spark,akopich/spark,bdrillard/spark,pgandhi999/spark,mahak/spark,apache/spark,joseph-torres/spark,ron8hu/spark,HyukjinKwon/spark,shubhamchopra/spark,shubhamchopra/spark,JoshRosen/spark,taroplus/spark,michalsenkyr/spark,hvanhovell/spark,nchammas/spark,xuanyuanking/spark,shuangshuangwang/spark,shaneknapp/spark,shuangshuangwang/spark,actuaryzhang/spark,ueshin/apache-spark,wangmiao1981/spark,bdrillard/spark,witgo/spark,zero323/spark,goldmedal/spark,aray/spark,cin/spark,rednaxelafx/apache-spark,saltstar/spark,kevinyu98/spark,WeichenXu123/spark,cloud-fan/spark,zuotingbing/spark,srowen/spark,WindCanDie/spark,esi-mineset/spark,sureshthalamati/spark,facaiy/spark,spark-test/spark,kiszk/spark,maropu/spark,jiangxb1987/spark,adrian-ionescu/apache-spark,JoshRosen/spark,zzcclp/spark,hvanhovell/spark,mahak/spark,dongjoon-hyun/spark,zzcclp/spark,joseph-torres/spark,lxsmnv/spark,akopich/spark,ddna1021/spark,debugger87/spark,skonto/spark,HyukjinKwon/spark,rednaxelafx/apache-spark,aray/spark,Aegeaner/spark,Aegeaner/spark,JoshRosen/spark,maropu/spark,ioana-delaney/spark,actuaryzhang/spark,spark-test/spark,nchammas/spark,ddna1021/spark,ericvandenbergfb/spark,chuckchen/spark,guoxiaolongzte/spark,taroplus/spark,Aegeaner/spark,dongjoon-hyun/spark,ericvandenbergfb/spark,xuanyuanking/spark,cin/spark,guoxiaolongzte/spark,caneGuy/spark,nlalevee/spark,ahnqirage/spark,ConeyLiu/spark,facaiy/spark,dongjoon-hyun/spark,zhouyejoe/spark,minixalpha/spark,wzhfy/spark,JoshRosen/spark,sureshthalamati/spark,1haodian/spark,dongjoon-hyun/spark,actuaryzhang/spark,ioana-delaney/spark,dbtsai/spark,sureshthalamati/spark,ericvandenbergfb/spark,sahilTakiar/spark,ueshin/apache-spark,markhamstra/spark,sahilTakiar/spark,tejasapatil/spark,kevinyu98/spark,cloud-fan/spark,ahnqirage/spark,akopich/spark,pgandhi999/spark,eyalfa/spark,lvdongr/spark,WindCanDie/spark,zuotingbing/spark,darionyaphet/spark,debugger87/spark,WindCanDie/spark,srowen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