AuthSettingsController: refactor rendering Instead of having one controller method ('auth_settings', which handles POST) call another controller method ('index', which handles GET), have both methods call a third, common '__render' method. This makes it clear which arguments 'index' really takes (none). It's also seen that the 'prefix_error' argument is always False, so it can be removed. Finally, '__load_defaults' is no longer called twice when POSTing invalid form values.