Sync Blender ID badge as soon as user logs in

This adds a new Blinker signal `user_logged_in` that is only sent when
the user logs in via the web interface (and not on every token
authentication and every API call).

pillar/api/utils/authentication.py

@@ -189,7 +189,7 @@ def validate_this_token(token, oauth_subclient=None):
         return None
 
     g.current_user = UserClass.construct(token, db_user)
-    user_authenticated.send(sender=g.current_user)
+    user_authenticated.send(g.current_user)
 
     return db_user