Flag for GitLab version selection

[FEATURE]

Details

If you scan a project on a GitLab Community instance, rules like 1.1.6 Ensure code owners are set for extra sensitive code or configuration are reported as Fail. However, the Code Owners feature is only available in Premium and Ultimate. Thus, I would argue that a missing CODEOWNERS file in a project on a GitLab community instance is a SKIP and not a FAIL.

It would be nice, if the gitlabcis script would either detect the variant of the GitLab server or if one could pass the variant as CLI option, and, then, the results would change from FAIL to `SKIP.

cc: @nmcd