CC PMF importer improvements

[lissyx]

The current code does not work well:

• extraction fails because Python zip does not support multiarchive, we should rely on 7z for example
• we should expose MIN_SECS / MAX_SECS to the command-line arguments
• document ffmpeg dependency for audio conversion
• we use multiprocess for performing one WAV split, but maybe we should also use multiprocess for converting multiple MP3 to WAV in paralell

[kishorhange111]

Hi @lissyx, can I pick this issue?

[lissyx]

You can but project is unmaintained, CI is most probably broken, and I dont have time for reviews.