Made new class ProxySpecialPage, which acts as a
proxy object to another SpecialPage object that is
determined based on context information other than
the title.
Then Special:OATH has been split into two separate
special page classes (both FormSpecialPages using
HTMLForm) that are routed to by a ProxySpecialPage
object.
In addition, the form for enabling two-factor auth
has been refactored into vform style, with some
better instructions on how to enable two-factor
authentication.
Change-Id: Ib9117cbc9d7f044de9607db81a157e1b472b5ec0
