Bundle brainstorm server dependencies instead of requiring npm install

Vendor node_modules into the repo so the brainstorm server works
immediately on fresh plugin installs without needing npm at runtime.

skills/brainstorming/scripts/node_modules/ws/browser.js

@@ -0,0 +1,8 @@
+'use strict';
+
+module.exports = function () {
+  throw new Error(
+    'ws does not work in the browser. Browser clients must use the native ' +
+      'WebSocket object'
+  );
+};