Rename auth classes for consistency

Summary: Ref T5655. Depends on D9998.

Test Plan: `arc unit`

Reviewers: epriestley, #blessed_reviewers

Reviewed By: epriestley, #blessed_reviewers

Subscribers: 20after4, epriestley, Korvin

Maniphest Tasks: T5655

Differential Revision: https://secure.phabricator.com/D9999