update: add Gitlab deletion host and task for user deletion requests

• update: add Gitlab deletion host and task for user deletion requests

To handle full GDPR, users should be hard removed from GL systems rather than kept around after the normal user deletion. While the account would be inaccessible, the name and account would be active. This could lead to additional notifications from a should-be deleted service as well as their name not being fully forgotten.

Resolves infrazilla#2001