Consider migrating off of using PATs and use managed identities/app auth instead

[missymessa]

Guidance from AzDO and GitHub has been to stop using PATs and start using managed identities and app auth, respectively. We still use PATs in many of our services, so this will be a large effort to refactor all these places. Sunsetting the use of PATs will improve our secret rotation experience, as well.

Release Note Category

• [ ] Feature changes/additions
• [ ] Bug fixes
• [ ] Internal Infrastructure Improvements

  Release Note Description

[davfost]

This is not in scope for the epic related to eliminating service principal secrets for the Helix service.

[missymessa]

I believe most of this will be done for AzDO with :ocean::one: work, but we will probably still need to do this for GitHub related PATs.