DocumentAuthor, rename author field to email and make it optional (for
modeling old email-less submissions), remove the authors many to many
referencing field from Document as it is not really pointing the right
place.
Update the Secretariat tools to show affiliation and country.
Add migration for getting rid of the fake email addresses that the
migration script created some years ago (just set the author email
field to null).
- Legacy-Id: 12739
