Merge pull request #928 from rjc123/newsites

Config nationalcollege.org.uk to match go-live plan
Update Certification Office transition date
Merge pull request #930 from alphagov/change_certoffice_date

Update Certification Office transition date
Merge pull request #929 from rjc123/newsites

Change go-live for decc blog
Configure new targets for bis legacy domains
Configure sigmascan on transition tool