As per the description in the JIRA, I moved the contents of the page and added a few additional content.

Author: Neelesh Srinivas Salian <nsalian@cloudera.com>

Closes #6924 from nssalian/SPARK-3629 and squashes the following commits:

944b7a0 [Neelesh Srinivas Salian] Changed the lines about deploy-mode and added backticks to all parameters
40dbc0b [Neelesh Srinivas Salian] Changed dfs to HDFS, deploy-mode in backticks and updated the master yarn line
9cbc072 [Neelesh Srinivas Salian] Updated a few lines in the Launching Spark on YARN Section
8e8db7f [Neelesh Srinivas Salian] Removed the changes in this commit to help clearly distinguish movement from update
151c298 [Neelesh Srinivas Salian] SPARK-3629: Improvement of the Spark on YARN document