Add Gitlab Contribution Cost Factor Docs and Remove flag

Merged Allison Browne requested to merge allison.browne-minutes-docs into master

Now ready to merge as verification term is complete. Flags Issues:

What does this MR do and why?

Add documentation and remove the flag for the gitlab community contribution cost factor.

Related MR: !89742 (merged)

Related Issue: #365447 (closed)

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

Edited by Allison Browne