Update fURLs to ones which work

The furls which didn't work wouldn't break any user journeys, because we only
ever use them for link text.

I removed one or two which didn't seem appropriate.
Merge pull request #833 from alphagov/remove_non_working_furls

Correct furls which don't work or aren't appropriate
Remove titles from site yaml

Transition is ignoring these titles, and uses the title from the Organisation
API instead.

Where there is an obvious title to use instead of the organisation title (or
the title was already different), I've done so.

This is part of allowing sites to have titles which aren't the organisation's
title.
Rename furl => homepage_furl

This more clearly explains the purpose of it. It should be a furl which
redirects to the same page as the homepage does.