Bug 1086930 - Add status region to sync calendar sync button

    Added a status area inside of the sync button this is only added to the a11y tree during syncing. It will specify that syncing has started and completed.
I was talking to some of they guys on the a11y team and I we agreed that the correct semantics for this is using a progress element. For changes we would use aria-valuetext (they are assigned in the similar way as the aria-label). I opened a bug on the gecko side to support global progress support here: https://bugzilla.mozilla.org/show_bug.cgi?id=1105770