Dynamic menus

We would like to add some additional menu items to the main navigation (e.g. link to the institute website).

Add assets/menu.json and fetch this file in client.tsx. Put the parsed JSON object to window.extMenus.

[
 {
  "title": "Intranet",
  "link": "https://intranet.local"
 },
 {
  "title": "Public website",
  "link": "https://www.institute"
 },
];

When rendering the top-level navigation, include items from window.extMenus below "Home".

This should not execute in SSR mode, only in the browser!