Forks of private forks should be removed if the upstream project is deleted

Problem to solve

When you have a group with your organization and you decide to lay off someone, you can remove them from your group, but they still own their forks of the private repositories from the organization. There's no option to remove those forks.

Further details

GitLab should try to preserve the ownership of private projects as best as possible. Although the local copy of the source code may still be at large, GitLab should do what it can to clean up.

Proposal

When a user or group has read access to private project revoked:

• automatically delete their forks of the private project

Links / references

• https://help.github.com/en/articles/what-happens-to-forks-when-a-repository-is-deleted-or-changes-visibility