Make site creation fail if the hostname is invalid

- In cases for example where it has a trailing slash.
- This uses URI.parse, which has to be given "http://" before the
  supplied hostname so that it works.
Revise known_sites tool to allow for focus on specific site abbrevs
Update domain checker to investigate www and non-www versions of domain in question
Configure PHE sites on transition app
Merge pull request #628 from rjc123/config-phe

Configure PHE sites on transition app
Adding three redirects for businesslink PDFs

Requested by DVLA - https://govuk.zendesk.com/agent/#/tickets/653587
be canonical
Merge pull request #629 from alphagov/add_more_businesslink_pdf_redirects

Adding three redirects for businesslink PDFs
Merge pull request #627 from rjc123/admin

Updates to some admin tools
[UKTI] Add ukti.gov.uk alias
Add resources.civilservice.gov.uk as alias to main site
Merge pull request #630 from rjc123/newsites

Add resources.civilservice.gov.uk as alias to main site
Configure archived PHE sites
Merge pull request #631 from rjc123/newsites

Configure archived PHE sites
Remove invalid furl from Official Documents pages
Merge pull request #632 from rjc123/newsites

Remove invalid furl from Official Documents pages
Change date for MMO
Merge pull request #633 from rjc123/newsites

Change date for MMO
Merge pull request #608 from alphagov/validate_hostnames

Make the `new_site` rake task fail if the hostname is invalid
New date for DCLG Local Finance