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.
> an opaque value that clients are required to understand?

I was thinking this. This is temporary, until we solve things for real, of course.