Don't tab stop on Hack links in proposal creation

It's really annoying when you are adding a proposal and you hit tab and
end up on the link to the Hack website. There's no need for this and at
least on newer browsers we can pretty easily skip the links for tab.

Unfortunately because this is model text it generates migrations. As we
know these migrations don't actually do anything, so they are annoying
but not actually harmful.

Taking one out of PyCon's (US) book

We're lock-step with symposion, and upstream is dead.
Vendor it.