(Re)Enable management of gitlab-shell resources

Summary

As part of the MVP, we elected to disable GitLab Shell as we were unable to derive an appropriate means to prove TCP ingress on OpenShift, which was the target for that Epic.

Now that we're byond this stage, we should look to selectively re-enable the management of resources from the chart. This would allow deployment & testing, at least on vanilla K8s.

Details

In vanilla k8s's, we don't have to worry about the Routes "problem". This should be usable with no issues. In OpenShift, when using the OpenShift NGINX Ingress Operator, we should be able to convince that deployed to accept TCP traffic to forward to GitLab. Further work regarding environment-specific items in routing may be required.