Make DiffusionCommitSearch accept modern (string) constants

Summary:
Depends on D19650. Ref T13197. Allow SearchCheckboxesField to have a "deprecated" map of older aliases, then convert them to modern values.

On the API method page, show all the values.

This technically resolves the issue in PHI841, although I still plan to migrate behind this.

Test Plan:

• Queried audits, fiddled with ?status=1,audited, etc.

Reviewers: amckinley

Reviewed By: amckinley

Maniphest Tasks: T13197

Differential Revision: https://secure.phabricator.com/D19651