R1:66392e5b8bb4

Add a rough "bin/repository unpublish" workflow to attempt to cleanup improperly published repositories

Summary:
Ref T13114. See PHI514. This makes some attempt to undo the damage caused by incorrectly publishing a repository.

Don't run this.

Test Plan: Yikes.

Maniphest Tasks: T13114

Differential Revision: https://secure.phabricator.com/D19271