Add the /runningpods/ api endpoint (#611)

* Add the /runningpods/ api endpoint

This adds an API endpoint from the kubelet (/runningpods/). It is
an endpoint on kubelet which is considered a "debug" endpoint, so
it might be worth exposing through the options, but by default
it is exposed in most k8s configs AFAICT.

virtual-kubelet/commands/root/http.go

@@ -86,7 +86,7 @@ func setupHTTPServer(ctx context.Context, p providers.Provider, cfg *apiServerCo
 		}
 
 		mux := http.NewServeMux()
-		vkubelet.AttachPodRoutes(p, mux)
+		vkubelet.AttachPodRoutes(p, mux, true)
 
 		s := &http.Server{
 			Handler:   mux,