Add Cleanup options as an "On Save" option

[nschonni]

#148 is adding some interesting file cleanup options to the pack.
Since not all repos like old documentation being updated, it would be nice to have it as an "on save" option so that newer/edited documents can be cleaned up as they are edited.

//cc @bharney-msft

AB#239490

[meganbradley]

Added to feature backlog.

https://ceapex.visualstudio.com/Engineering/_workitems/edit/78704

[meganbradley]

Added help wanted tag. We need to figure out how to make this work with auto-save turned on, so it's not running constantly. It should be configurable in VS Code settings, off by default.

[meganbradley]

@mamccrea do you still have interest in doing this one?

[mamccrea]

@meganbradley - we can work on it, but we moved all of our efforts to unit test coverage. I unassigned myself because I didn't want to hold it up if someone else wanted to take it.