Merge branch 'selhorn-contrib-update' into 'master'

Reorganized and removed top-level page

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/127795



Merged-by: Kati Paizee <kpaizee@gitlab.com>
Approved-by: Kati Paizee <kpaizee@gitlab.com>
Reviewed-by: Achilleas Pipinellis <axil@gitlab.com>
Reviewed-by: Kati Paizee <kpaizee@gitlab.com>
Co-authored-by: Suzanne Selhorn <sselhorn@gitlab.com>