Merge pull request #497 from rjc123/newsites

Configure dasa.mod.uk on transition-sites
Tweak the new homepage for Life in the UK Test

Fran/Till agreed that the guide is better than the transaction start page.
Update the UKBA/UKVI switchover date
Resolve zendesk ticket to unpublish business link assets https://govuk.zendesk.com/tickets/542756
Merge pull request #499 from rjc123/zendesk

Resolve zendesk ticket to unpublish business link assets https://govuk.z...
Add an initial Environment Agency site

I used the most recent TNA crawl datetime. I had a brief look for significant
querystring parameters. There are definitely some, but I didn't want to do half
a job; better that it obviously hasn't been done.
Merge pull request #498 from alphagov/add_ea

Add an initial Environment Agency site
Resolve canonicalisation failures.
Merge pull request #501 from rjc123/zendesk

Resolve canonicalisation failures.
Add Jenkins branch build script
Configure www.apc.gov.uk legacy domain