feat: added vue examples

This PR includes Vue examples, in particular:
- Vue Spa
- Vue Spa + Router
- Vue using Sever Side Rendering with Express.js.

Also updated the general Readme.

vue/ssr/client.js

@@ -0,0 +1,3 @@
+import { createApp } from './src/app.js';
+
+createApp().mount('#app');