UC-21 Disable/remove push notifications from facebook Connect

The functionality for push notifications for Facebook connect has been broken for some time (see UC-20). This ticket cleans up all of the broken Facebook Connect code which had to do with pushing notifications, and removes all the references to that feature on the user facing side.

Ticket: https://wikia-inc.atlassian.net/browse/UC-21
At that point we can update the config file. I'd prefer to leave it out for now.