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. 
Registering this hook takes place [here](https://github.com/Wikia/app/blob/UC-107/extensions/wikia/Oasis/Oasis_setup.php#L49), inside the Oasis_setup.php file. This means that even when FBClient is enabled, this hook is getting run on every page load even though it doesn't end up doing anything. How about we move registering this hook into FBConnect.php so it's only run when FBClient isn't on?