* Add force_login option to OAuth authorize page
For when a user needs to sign into an app from multiple accounts
on the same server
* When logging out from modal header, redirect back after re-login
Setting of locale in controller extracted to Localized concern,
the doorkeeper authorized applications controller moved under
custom namespace with inclusion of Localized, which resolves the
"it sometimes appears in a different random language" bug
Thibaut Girka