title: Possible to have multiple `manifest.json` for PWA?
body: <p>Consider I have:-</p>
  
  <ul>
  <li>PWA at <code>myapp.firebaseapp.com</code> with it's own <code>manifest.json</code>.</li>
  <li>Admin for the PWA at <code>myapp.firebaseapp.com/admin</code></li>
  </ul>
  
  <p>Is it possible to have another <code>manifest.json</code> for the admin URL to allow "Add to Home Screen" on the same PWA?</p>