Currently emails are brought in by the OpenID login, but for example I use a different email address in my git commit than the one given by openid.

So we should have a way to:
- Add email to an account
- Mark email as pending
- Send notification to user with link to validate the email address
- Clean older validation token that expired
- Move the email to the UserEmail table (as active)

I'm thinking we should use a dedicated table in the DB for this making it easier to clean up.