Introduce NodeJS codegen for Google Cloud Functions. (#4406)

* Another approach: extending NodeJS server to support GCF.

This does not add a new language, but adding some client options
to support Google Cloud Functions (GCF).

* Add URLs for how to deploy the generated code.

Adds the client options help message and the README.md file.

samples/server/petstore/nodejs-google-cloud-functions/controllers/User.js

@@ -0,0 +1,39 @@
+'use strict';
+
+var url = require('url');
+
+
+var User = require('./UserService');
+
+
+module.exports.createUser = function createUser (req, res, next) {
+  User.createUser(req.swagger.params, res, next);
+};
+
+module.exports.createUsersWithArrayInput = function createUsersWithArrayInput (req, res, next) {
+  User.createUsersWithArrayInput(req.swagger.params, res, next);
+};
+
+module.exports.createUsersWithListInput = function createUsersWithListInput (req, res, next) {
+  User.createUsersWithListInput(req.swagger.params, res, next);
+};
+
+module.exports.deleteUser = function deleteUser (req, res, next) {
+  User.deleteUser(req.swagger.params, res, next);
+};
+
+module.exports.getUserByName = function getUserByName (req, res, next) {
+  User.getUserByName(req.swagger.params, res, next);
+};
+
+module.exports.loginUser = function loginUser (req, res, next) {
+  User.loginUser(req.swagger.params, res, next);
+};
+
+module.exports.logoutUser = function logoutUser (req, res, next) {
+  User.logoutUser(req.swagger.params, res, next);
+};
+
+module.exports.updateUser = function updateUser (req, res, next) {
+  User.updateUser(req.swagger.params, res, next);
+};