Introduce permission for allowing space managers to delete their spaces #2962

This idea originated here: #1799 (comment). I'm just creating this issue to keep track of it because the original issue got closed.

So it should be possible to create a custom user role that gives spaces managers the permission to delete their assigned spaces. Possibly either by introducing a new permission, or by adding a constraint to the existing Drives.DeleteProject permission. See the linked comment for more context and details.