Support the org permissions cleanup initiative

[galargh]

Related to #115, #113 and #104

This PR:

• ensures that properties of archived repos (other than archived) are hidden from view since they cannot be modified
• fixes setting GitHub Actor for auto-generated commits (no longer associated with last committer unless triggered via workflow dispatch)
• adds reporting on access changes from user perspective on every PR
• prevents github management from creating empty commits when a changes to attributes of github_repository_file other than content are detected

TODO:

• [ ] @galargh - use diff in the summary of access comment instead of the state after the change is applied