Merge branch 'rd-groups-api-resources-list' into 'master'

Improve structure of REST API groups topics

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/169867



Merged-by: Suzanne Selhorn <sselhorn@gitlab.com>
Reviewed-by: Marcel Amirault <mamirault@gitlab.com>
Co-authored-by: Marcel Amirault <mamirault@gitlab.com>
Co-authored-by: Russell Dickenson <rdickenson@gitlab.com>