Set window.org and window.app without requiring the app Index.cshtml to do so

[olemartinorg]

Description

In all apps today, the following lines of javascript are present:

<script>
  const appId = window.location.pathname.split('/');
  window.org = appId[1];
  window.app = appId[2];
</script>

It's silly, we could do this in app-frontend instead, and save apps these lines of code.

We could likely do this today, at least setting the values if they're not set yet, but in v5 we could remove this from the index file altogether as well.

Also, we'd have to talk to Studio when doing this, to make sure their frontend preview solution still works.

Additional Information

• https://digdir.slack.com/archives/C0760NPT2BE/p1733146273586509?thread_ts=1733145935.053809&cid=C0760NPT2BE