Andy, Michal & Sam: Repeating flow 😱

😱

Some notes:

 * Try to keep date stuff in one place.
 * We still need to get rid of the whole 'update_draft' stuff - they don't actually do anything.
 * For a section with subsections, the data for each subsection goes into draft.<section>.<subsection>
 * The data for an ordinary page still just goes into draft.
 * Error conditions with sections/subsections names and deciding where should we redirect to if user has bookmarked an old or no longer relevant page?