Add webpack for external frontend libraries.

src/middleware/webpack-serve.js

@@ -0,0 +1,9 @@
+import webpack from 'webpack';
+import middleware from 'webpack-dev-middleware';
+import { publicLibConfig } from '../../webpack.config.js';
+
+export default function getWebpackServeMiddleware() {
+    const compiler = webpack(publicLibConfig);
+
+    return middleware(compiler, {});
+}