R1:cf4eb3109e77

Allow projects to review revisions

Summary:
Ref T1279. No actual logical changes, but:

- You can now add projects as reviewers from the revision view typeahead ("Add Reviewers" action).
- You can now add projects as reviewers from the revision detail typeahead.
- You can now add projects as reviewers from the CLI (`#yoloswag`).
- Generated commit messages now list project reviewers (`Reviewers: #yoloswag`).

I'll separate projects from users in the "Reviewers" tables in the next revision.

Test…