Remove ApplicationInterface.
Rename Variant as Service.
Remove serviceSecret.
Update Alias as Username and Category as Scope.
Update Alias as Username and Category as Scope.
Add MessageId.
Re-add authbucket/oauth2-php.
Basically revoke test setup with oauth2-php.
Revamp firewall from HTTP Basic to OAuth2.
Revamp registerAction in plain POST style.
Revamp unregisterAction in plain POST style.
Merge branch 'feature/oauth2' into develop