This does some backend cleanup of the tile stuff, and some general cleanup of other application things:
- Users who haven't customized preferences get a small, specific set of pinned applications: Differential, Maniphest, Diffusion, Audit, Phriction, Projects (and, for administrators, Auth, Config and People).
- Old tile size methods are replaced with isPinnnedByDefault().
- Shortened some short descriptions.
- shouldAppearInLaunchView() replaced by less ambiguous isLaunchable().
- Added a marker for third-party / extension applications.