Port forward over websockets

- split out port forwarding into its own package

Allow multiple port forwarding ports
- Make it easy to determine which port is tied to which channel
- odd channels are for data
- even channels are for errors

- allow comma separated ports to specify multiple ports

Add  portfowardtester 1.2 to whitelist

pkg/client/tests/portfoward_test.go

@@ -84,7 +84,7 @@ func fakePortForwardServer(t *testing.T, testName string, serverSends, expectedF
 			received: make(map[uint16]string),
 			send:     serverSends,
 		}
-		portforward.ServePortForward(w, req, pf, "pod", "uid", 0, 10*time.Second)
+		portforward.ServePortForward(w, req, pf, "pod", "uid", 0, 10*time.Second, portforward.SupportedProtocols)
 
 		for port, expected := range expectedFromClient {
 			actual, ok := pf.received[port]