## What changes were proposed in this pull request?

Updated setJobGroup, cancelJobGroup, clearJobGroup to not require sc/SparkContext as parameter.
Also updated roxygen2 doc and R programming guide on deprecations.

## How was this patch tested?

unit tests

Author: Felix Cheung <felixcheung_m@hotmail.com>

Closes #13838 from felixcheung/rjobgroup.