Drive auth config with the database
Summary: Ref T1536. This is the last major migration. Moves us over to the DB and drops all the config stuff.
Test Plan:
- Ran the migration.
- Saw all my old config brought forward and respected, with accurate settings.
- Ran LDAP import.
- Grepped for all removed config options.
Reviewers: btrahan, chad
Reviewed By: btrahan
CC: aran, wez
Maniphest Tasks: T1536
Differential Revision: https://secure.phabricator.com/D6243