Change the homepage for statistics.gov.uk

- The final part of this story is to change the title of this, but we no
  longer store titles in site config .yml files.
Add the homepage_title field as 'Statistical Announcements'
Merge pull request #869 from rjc123/newsites

Revise MIS go-live information
Merge pull request #870 from rjc123/newsites

Change date of Natural England transition
Merge pull request #868 from alphagov/update_statistics.gov.uk

Change the homepage for statistics.gov.uk
Change timestamp for actonco2.direct.gov.uk
Change timestamp for careandsupport.direct.gov.uk
Change timestamp for communitypayback.direct.gov.uk
Change timestamp for oneplace.direct.gov.uk
Change timestamp for sciencesowhat.direct.gov.uk
Merge pull request #871 from alphagov/directgov_legacy_timestamps

Change a load of Directgov legacy domain timestamps to be actual pages
Date change for landregistry