Now that we have effective global sessions thanks to #2734, there is no
longer a need to keep the number of pods on the EPP service static.
We are also not vulnerable to random pod restarts. K8s never guarantees
perpetual pod lifetime anyway, and not having to be at its mercy is
certainly a relief.
This allows us to easily tell which tag was deployed.
Also set the gateway to use named address so they are stable, and so
that we can attach an IPv6 record to it. Auto-provisioned addresses are
IPv4 only.
k8s does not have a way to expose a global load balancer with TCP
endpoints, and setting up node port-based routing is a chore, even with
Terraform (which is what we did with the standalone proxy).
We will use Cloud DNS's geolocation routing policy to ensure that
clients connect to the endpoint closest to them.
