Create supporting infrastructure for cdn.registry.gitlab.com

This issue tracks the work to create the Google Cloud CDN in the production environment.

• Chart bump in production gitlab-com/gl-infra/k8s-workloads/gitlab-com!1465 (merged)
• Create the CDN LB with the Registry LB as an origin in Terraform https://ops.gitlab.net/gitlab-com/gl-infra/config-mgmt/-/merge_requests/3322 https://ops.gitlab.net/gitlab-com/gl-infra/config-mgmt/-/merge_requests/3328
• Validate that we can retrieve cached objects from the bucket via the CDN
• Validate the k8s secret is created gitlab-com/gl-infra/k8s-workloads/gitlab-com!1466 (merged)