Add Badges to UserCache
Summary: Ref T12270. Builds out a BadgeCache for PhabricatorUser, primarily for Timeline, potentially feed? This should still work if we later let people pick which two, just switch query in BadgeCache.
Test Plan: Give out badges, test timeline for displaying badges from handles and without queries. Revoke a badge, see cache change.
Reviewers: epriestley
Reviewed By: epriestley
Subscribers: Korvin
Maniphest Tasks: T12270
Differential Revision: https://secure.phabricator.com/D17503