Add a setting for allowing/disallowing duplicate generic package uploads
Problem to solve
When using the GitLab Package Registry to publish generic packages, a duplicate package name/version can be uploaded. This may be great in some cases but not if the package should be immutable.
Add a setting that will allow you to define (at the group level) whether or not duplicate generic packages are allowed and allot for exceptions.
Add an end to end level test similar to the one done for Maven