Review Apps for CE/EE

I think we have nearly all that we need to deliver Review Apps for CE/EE users:

1. An existing CI job that builds a docker image for a branch and publishes to public GitLab registry.
2. A Helm chart which can accept any GitLab image and run it in Kubernetes.

The work item I think we need to do here, is to set the review app build job to create the new CNG containers. (Probably just the rails container?)

• The new charts can accept existing SSL certificates
• Can also skip deployment of kube-lego and ingress, which we don't want on a shared cluster
• The current charts are deprecated and we don't want to maintain some special version.

This means we have a lot of the foundation in place to set up review apps.

To support SS, we could:

• Use a wildcard certificate and set the URL's of each endpoint to be unique.
  • For example, a deployment of GitLab Rails could be CI_ENVIRONMENT_SLUG-gitlab.x.y. The Registry could then be ``CI_ENVIRONMENT_SLUG-registry.x.y`, etc.
• With the CNG charts, provide a common wildcard certificate and skip deployment of kube-lego and nginx-ingress
• Utilize a shared cluster, and avoid having to automate DNS setup for each new cluster's public IP