Data migration to fix publication unpublishing

This publication was mistakenly set to "archived" instead of being
"unpublished". This data migration corrects the unpublishing, setting up
the redirect, and also sets the edition state back to "draft",
completing the unpublishing process.
Fix a document 404ing with a redirect

www.agileplannerapp.com/boards/173808/cards/5678

it seems 2 editors started working on separate
drafts for the same content, hence there were
duplicate documents. the content lives at the
url that contains the slug with a sequence
number. hence redirecting to that location.
Merge pull request #1679 from alphagov/fix-publication-unpublishing

Data migration to fix publication unpublishing
Merge pull request #1680 from alphagov/fix-document-404ing

Fix a document 404ing with a redirect