mpv: Move into multimedia module

multimedia/README.md

@@ -1,6 +1,12 @@
-# mpv module
+# Multimedia module
 
 [mpv](https://mpv.io) -- free, open-source, cross-platform media player
+beets -- organize your music library
+mopidy -- serve your music library
+ncmpcpp -- actually play your music (and twist your tongue pronouncing it)
+
+The largest modifications so far are definitely to mpv (described below),
+with beets and mopidy being somewhat configured to my tastes as well.
 
 mpv is set up to hopefully strike a balance between high quality playback, streaming with a reasonable speed and saving battery power.
 It is set up to play both local files and streams from the web (especially youtube with playlisting and ad skipping), via a qutebrowser mapping if the corresponding module is installed.