Summary:
Ref T8498. I want to add Spaces to these, and the logic for getting Spaces right is a bit tricky, so swap these to ApplicationTransactions.
One new piece of tech: made it easier for Editors to raise DuplicateKeyException as a normal ValidationException, so callers don't have to handle this case specially.
One behavioral change: we no longer require these addresses to be at the `auth.email-domains` domains -- I think this wasn't quite right in the general case. It's OK to require users to have `@mycompany.com` addresses but add `@phabricator.mycompany-infrastructure.com` addresses here if you want.
Test Plan:
- Tried to create a duplicate email.
- Tried to create an empty email.
- Tried to create an invalid email.
- Created a new email.
- Deleted an email.
Reviewers: btrahan
Reviewed By: btrahan
Subscribers: epriestley
Maniphest Tasks: T8498
Differential Revision: https://secure.phabricator.com/D13246
