This introduces moving the port definitions for admin services to
a headless Service -- varnish-ingress-admin in admin-svc.yaml. Services
that implement Ingress with Varnish are identified by this Service:
label app=varnish-ingress and at least the port named varnishadm,
possibly also the admin ports for the haproxy offloader (dataplane
and faccess).

And update the "golden" files for testing generated templates.

- Add a Unix socket listerner for the offloader.
- Use VCL 4.1 (required when Unix sockets are in use).

Starting with a pristine cluster, it initially deploys the controller
and unready Services for Varnish Ingress, and verifies the deployment.

Then each of the examples are deployed, verified, and undeployed.

On exit the Services for Ingress and controller are undeployed,
restoring the pristine state of the cluster.

Deployment is now in the API group apps/v1.

RBAC for the namespace example was missing rules to access resources
in the ingress.varnish-cache.org APIs.

Otherwise no backend is set for background fetches.

Newer versions of the RPMs for compatibility with Varnish 6.2
evidently do not express dependencies narrowly enough.

Closes #24