Allow Kube proxy to watch for service/endpoint changes

Expose `GET /endpoints/<serviceName>`.  Allow watch on endpoints and with services with `fields=Name%3D<serviceName>`
See my comment in the other PR - since you can't do function equality checks, if nil is not passed then there's no current way to treat Everything as "don't do inefficient things".  We should convert it to an interface if that's where we're going.  I'll convert it here though.