Remove redirector scenarios

Traffic for all transitioned domains now goes to Bouncer, and Redirector
is being decommissioned. There is a separate feature for Bouncer which
checks that the app is functioning, and this isn't the appropriate place
for any further tests of its behaviour.
Rename feature testing gov.uk redirect to www
Merge pull request #109 from alphagov/remove_redirector_features

Remove redirector features