feat: Adding cloudflare service definition
Part of gitlab-com/gl-infra/scalability#2917 (closed)
This will allow cleaning up workarounds such as https://gitlab.com/gitlab-com/runbooks/-/blob/master/mimir-rules-jsonnet/utilization.jsonnet?ref_type=heads#L41-L48, where we fake a service definition to generate code.
We need this service definition to provide a real definition to the cloudflare utilization metric.
We can tackle the code refactorings to remove the fake definitions after merging this in a follow up MR(s).