Output mode for printing playlists of similar tracks

[iammordaty]

Hello! In musly command line tool, I added the ability to change output mode. The new mode allows printing a playlist of similar tracks in a similar way as when listing files from the collection.

Please see an example outputs below:

$ musly -p test/2.mp3 # or: musly -o short -p test/2.mp3
[...]
Computing the k=5 most similar tracks to: test/2.mp3
audio/3.mp3
test/1.mp3
test/5.mp3
test/4.mp3

$ musly -o long -p test/2.mp3
[...]
Computing the k=5 most similar tracks to: test/2.mp3
track-id: 3, track-distance: 0.720967, track-origin: test/3.mp3
track-id: 2, track-distance: 0.837826, track-origin: test/1.mp3
track-id: 1, track-distance: 0.910639, track-origin: test/5.mp3
track-id: 4, track-distance: 0.93015, track-origin: test/4.mp3

[iammordaty]

Hi, @f0k! Is there any chance of accepting this MR? If I should change anything else, please let me know. Thanks!