R1:8909f8ec599b

Modernize OAuthServer PHIDs and Queries

Summary:
- Modernize PHID types.
- Implement `PhabricatorPolicyInterface`.
- Make queries policy aware.

Test Plan: Browsed client and authorization lists.

Reviewers: btrahan

Reviewed By: btrahan

Subscribers: chad, epriestley

Differential Revision: https://secure.phabricator.com/D8560