Support categories as a second level side menu in PWA (self hosted)

[aptalca]

Is your feature request related to a problem? Please describe. If there are categories involved (added through xtream api), the playback screen only shows the channels in that same category and if the user wants to switch to a channel in a different category, they would be spit back to the category selection screen and the playback stops.

Clicking All Categories in the above screenshot stops playback.

Describe the solution you'd like It would be really nice if the categories could be browsed in a second layer of the side menu.

The above screenshot is from a different web player and it makes it much easier to switch to a channel in a different category while keeping playback active until the switch. Clicking on a different category simply updates the channel list in the second tab and playback is unaffected.

Describe alternatives you've considered EDIT: I just noticed that if I add a simple m3u, it does use a different collapsible side bar with multiple tabs. Perhaps that same bar with the tab functionality could be adapted to browse categories and used for xtreme api added playlists as well.

Additional context Self hosting the backend and the PWA frontend in a docker container.