Add publication format to edition view

Make it clear what type of format is being viewed. Also shorten text
used for editions and statuses.
Update to content models 27.0.0
Merge pull request #332 from alphagov/update_govuk_content_models

Update to content models 27.0.0
Merge pull request #330 from alphagov/format-on-edition

Add publication format to edition view
Bump admin gem to 1.4.2

Pull in fix for wrapping environment label