Implement SBS plugin which forces username change during login for users who have email like username.
Allow change to username which is not in nukes_users, or is here with users email address (so is duplicity account for this user).

This functionality must interact with duplicity synchronization functionality too, and fill necessary user profile fields correctly (sync flag and field with information about duplicit accounts).

So then our jira plugin used to solve duplicit accounts shows this renamed users in jira too and allows us to rename them in jira correctly.