Uc 107 Re-enabling notification to users upon successful facebook signup

The old FBConnect extension had a banner message (GlobalNotification) when the user signup up with facebook. It was triggered by a GET string of `fbconnected=1`. This PR adds this functionality into the FacebookClient extension. 

Note: I didn't carry over the error case b/c I'm assuming we're already handling it before any redirects. 

I also implemented a more permanent solution for https://wikia-inc.atlassian.net/browse/CON-1856. Turns out when the notifications are appended to `.WikiaPageContentWrapper`, as they are with JS, the z-index works fine. I just updated the Php version to work like the JS version and it's displaying correctly now, so I removed the `autoHide()` call from GlobalNotification.js. @rafalkalinski please let me know if this looks okay to you. 
Should this be escaped()? Doesn't look like NotificationsController::addConfirmation does any escaping on its own.