[rt-users] A new home for the wiki

[Jesse Vincent]

> I REALLY miss the old wiki.  Why did we switch?  

A large part of the reason for the switch was anti-spam. Running the
project wiki on its own was a constant battle against the spammers.
Wikia is much better able to leverage their scale to stop the spammers.

I agree that we need to address the search issue. It really does look
like something is _wrong_, not just poorly done.