Make optout link more AJAXy

Make it grey, unclickable and change text while waiting for the
AJAX request.

Change-Id: Ic5c2923944658d5be04217cdfe62e1d8608a478f
Mingle: https://wikimedia.mingle.thoughtworks.com/projects/multimedia/cards/723
Merge "Make optout link more AJAXy"