Ability to update authorized groups separately from full request

[ssalinas]

This PR does a few things:

• Allows a readWrite user to update readWriteGroups or group as long as they are authorized for both the new and old groups
• Adds an endpoint to only update group, readWriteGroups, readOnlyGroups for a request, without needing to post the full request body
• Adds an endpoint to verify a user is authorized to perform a group update on a request

[matush-v]

🚢 ☘️