Organize OperatorGroup doc

[anik120]

The doc on OperatorGroup has a lot of valuable information in it, but reading the doc as a whole feels like it's different excerpts thrown in together (instead of the doc reading like a single page of a book).

This prevents readers from knowing where to find the relevant material within the doc, especially since searching for key words in the search box also does not produce good results.

Rearranging the doc to read like a single page on OperatorGroup (possibly with a section in Troubleshooting that contains troubleshooting answers for FAQs, with a link from the main OperatorGroup doc to the troubleshooting section), could help communicate the same information better.