Optimized upstream & loadbalancer

- Test and optimized load balancer origin picker
- Fixed no active origin cannot load proxy rule bug
- Implemented logger design in websocket proxy module
- Added more quickstart tours
- Fixed #270 (I guess)
- Fixed #90 (I guess)

src/mod/sshprox/sshprox.go

@@ -88,6 +88,7 @@ func (m *Manager) HandleHttpByInstanceId(instanceId string, w http.ResponseWrite
 		wspHandler := websocketproxy.NewProxy(u, websocketproxy.Options{
 			SkipTLSValidation: false,
 			SkipOriginCheck:   false,
+			Logger:            nil,
 		})
 		wspHandler.ServeHTTP(w, r)
 		return