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/inherits/inherits.js

@@ -0,0 +1,9 @@
+try {
+  var util = require('util');
+  /* istanbul ignore next */
+  if (typeof util.inherits !== 'function') throw '';
+  module.exports = util.inherits;
+} catch (e) {
+  /* istanbul ignore next */
+  module.exports = require('./inherits_browser.js');
+}