Move account passwords to shared infrastructure
Ref T13043. This moves user account passwords to the new shared infrastructure.
There's a lot of code changes here, but essentially all of it is the same as the VCS password logic in D18898.
- Ran migration.
- Spot checked table for general sanity.
- Logged in with an existing password.
- Hit all error conditions on "change password", "set password", "register new account" flows.
- Verified that changing password logs out other sessions.
- Verified that revoked passwords of a different type can't be selected.
- Changed passwords a bunch.
- Verified that salt regenerates properly after password change.
- Tried to login with the wrong password, which didn't work.
Reviewed By: amckinley
Maniphest Tasks: T13043
Differential Revision: https://secure.phabricator.com/D18903