navidrome: disable auto-import of .m3u playlists found in the library

ND_AUTOIMPORTPLAYLISTS defaults to true and was importing every .m3u it
found scanning the music folder (one per album from ripping software) as
a playlist -- 2059 of them, 1605 completely empty, hundreds duplicated.
Cleaned up the existing junk via the Subsonic API; this stops it from
coming back on the next scan.

navidrome/docker-compose.yaml

@@ -5,6 +5,7 @@ services:
     restart: unless-stopped
     environment:
       - ND_MUSICFOLDER=/media/music/albums
+      - ND_AUTOIMPORTPLAYLISTS=false
       - ND_LOGLEVEL=info
       - ND_PORT=4533
       - TZ=America/New_York