Patch for join box

[Paul W. Frields]

Attached is a patch that adds a pretty "Get an account" message on our
fp.o/join-fedora page.  We want to make sure people can jump right to
the good stuff if possible.  This URL will be a landing point for anyone
who gets a physical CD/DVD, because the "join.fedoraproject.org" URL is
printed on their sleeves.  The patch is deceptively large because the
insertion changes a lot of line numbers in the PO files; sorry. :-)

I await your review and comments, O webmasters!