In https://gitlab.com/gitlab-org/gitlab/-/merge_requests/96336 and
https://gitlab.com/gitlab-org/gitlab/-/merge_requests/98010, we added
support for Google CDN in front of CI artifacts to improve performance
and reduce costs. This commit adds the necessary configuration support
to enable it.

This is similar to the work for the container registry in
https://gitlab.com/gitlab-org/charts/gitlab/-/merge_requests/2328.

Relates to https://gitlab.com/gitlab-org/charts/gitlab/-/issues/3711