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/is-binary-path/index.js

@@ -0,0 +1,7 @@
+'use strict';
+const path = require('path');
+const binaryExtensions = require('binary-extensions');
+
+const extensions = new Set(binaryExtensions);
+
+module.exports = filePath => extensions.has(path.extname(filePath).slice(1).toLowerCase());