[FEATURE] Be able to fully remove user from EUS database

[Danny-dK]

Is your feature request related to a problem? Please describe.

Removing a user from iRODS Yoda does not remove it from external user service (EUS) database. This then result in not being able to resend an invite to an external user by removing and adding the user again in Yoda iRODS. It furthermore would go against personal data retention limitation of the GDPR to retain email addresses indefinitely?

Describe the solution you'd like

Be able to remove a user fully.