Hide navigation bar in standalone PWA

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Is your feature request related to a problem? Please describe.
I use a PWA on my phone for one Nextcloud app which doesn't have a (good) native app available.
It's nice because it acts mostly like any other app, with the correct icon and so on.
Unfortunately the experience of using the PWA itself is a bit weird, because I still see the navigation bar. In a standalone PWA for a single Nextcloud app (you could have multiple PWAs for each Nextcloud app you need) I really don't need to see the navigation bar. The same goes for the account menu, but maybe in some cases there are valid reasons, e.g. if you need to go to the settings which change something for the current app.

Describe the solution you'd like
The navigation bar should be hidden either entirely or at least the entries for the other apps should not be shown, if the user accesses the app as a standalone PWA.