Podcast issues:

- cover art for podcasts: 
    - use the coverart embedded in the actual mp3
    - use generic image or cover.jpg inside the podcast folder
    - download a cover.jpg for the podcasts already in the library right now
- podcasts grouping right now is not optimal. right now the hierarchy is for example "Sendung mit der Maus" => "Sendung mit der Maus" => "actual tracks". I'd rather like: "Sendung mit der Maus" => all tracks shown as separate cards so that their cover art is shown. The normal track list view (textbased) should be replaced by this.
- when playing a podcast, the timer "Noch ... im Hörbuch" doesn't make sense.  Hide it in case of podcasts. also stop playing after one podcast episode. For albums and real audiobooks stop after the audiobook or album played fully.


think about a datamodel for podcasts that is elegant, fits with what we have and then check back with me before implementing.


UI issues:
- setting the volume reacts very slowly right now. investigate. fix only if it is possible without massive workarounds.
  plan a fix and check with me first.
- the seek bar is behaving weird: when I click on a position it moves there, but then it moves sligtly backwards (probably after a backend state update). Find the cause and check the fix with me before implementing.
  when skipping to the next song it also moves slowly to the beginning

- in the overview create category sections (3 rows) for music, audiobooks, podcasts.
  the rows should scroll horizontally. for each row there is a search button that searches only this group