Add simple service redirection

This adds a simple redirection handler, so that you can call ```GET /api/v1beta1/redirect/services/myService``` and get back a 307 and a Location header set with an IP:port that will let you talk to myService. This is a very rudimentary form of discovery that is inferior to our final solution in every way except for existing.

@smarterclayton This is a simple idea about how to send requests to a service running in a k8s cluster from outside of that cluster, inspired by the conversation about having a build system. This would NOT be the way I expect to talk to actual k8s plugins.
Agree it shoudn't be generic, but 404 doesn't seem right, either. It's not that we couldn't find the service, it's that it's down. Can we punt on this until we get an error package that doesn't require importing apiserver? :)