feat(group): merge requests related options

Summary

• closes #6102
• closes #6103

I am not really sure the options are currently available under the GitLab API.

The documentation does not mention them: https://docs.gitlab.com/ee/api/groups.html#new-group

But is it automatically updated according to the API recent changes?

If not available but open for contribution, I may willing on that if you give me some hints. :-)

Regards