Add a "bin/audit synchronize" command

Summary: Ref T10978. This is just a maintenance convenience script. It can fix up overall commit state after you bin/audit delete stuff or nuke a bunch of stuff from the database, as I did on secure.phabricator.com.

Test Plan: Ran bin/audit synchronize, and bin/audit update-owners.

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T10978

Differential Revision: https://secure.phabricator.com/D17271