Add a Status and a $reason parameter to TitleMove hook

Add a Status and a $reason parameter to TitleMove hook

So that using this hook it's possible to prevent the move, also
providing some more context.
Also, clean error message: instead of going with "you do not have
permission blah blah" for *every* kind of error, use it only when the
error is actually about permissions, and use a generic message
otherwise.

Bug: T208907
Change-Id: I4733724075b7514e9db59e7be772d9409aa9da87