Remove uses of Special:GettingStarted from task toolbar

* Remove now-unneeded dependencies
* Don't put everything in doc ready, so AJAX request can kick off before it.
* Tweak CSS to accomodate removed 'back to list'
* If AJAX request fails, try again when they click.  If it still fails,
  notify them at that point.

Change-Id: I315352b72f9dd148c02e2078f22ca493d1f20dd9
Merge "Remove uses of Special:GettingStarted from task toolbar"