Previously when clicking the Delete button for small action posts
there was no way to recover this post if the action was accidental.
Now if canRecover is true on the post, which it is just after it
is deleted and the post is fetched from the server again, we show
an undo button which calls the recover endpoint for the post.
We also now disallow the editing of the post if it is deleted, and
show the proper deleted red CSS on the small action post when deleted.
