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
Yea, I feel the same way. Leaving references to code which is no longer present or supported feels crufty. We can just revert this whole merge if we do decide to return to push notifications.