Edit project display name on delete (activated_state = "inactive")

[lcjohnso]

I ran into an issue where a project name/slug was not accepted for use because there was a duplication between the new proposed project display_name and the display_name of a deleted project. Namely: User A creates Project X with display_name="My Project", deletes Project X.
User A then creates new Project Y, but is not allowed to use display_name="My Project" for Project Y because the name/slug of "user-a/my-project" is still assigned to Project X.

Proposed Behavior: When a project is deleted, the display name is changed to append "DELETED: " to the beginning. This will eliminate future project name/slug collisions.

[lcjohnso]

Related: #2710

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[lcjohnso]

Not stale, stalebot!

[lcjohnso]

Closed by #4279