It would be useful to run control plane outside of the cluster using local processes. Imagine pilot and mixer running locally using go run against a k8s cluster with injected apps, and the apps are talking to the local pilot and mixer. For that to happen, we need a reverse tunnel to k8s proxy:

1. proxy listens for external IP connections, exposes itself as a k8s service istio-pilot and istio-mixer.
2. a helper creates a tunnel, that bridges local pilot and mixer to the remote proxy.