Visual enhance mobile representation of appstore

Please provide the following details for error reports from https://apps.nextcloud.com/. Ignore in case of a feature request.

## Details

* Browser and browser version: Latest Firefox on Android

## JavaScript Console Output

_None_

## Feature Request

The styling is rather counter-intuitive as a long list of categories is on the top and you have to scroll down in order to get to the apps (especially if you have entered a search string before). Also, the names of the apps use a large fond leading to ellipses and guessing of the names.

It might be an option to generally rework the UI for (portrait) mobile clients.