feat: get alternatives

[OhMyMndy]

Sometimes tracks aren't available anymore because of rights.

This PR fetches alternative tracks if they are defined, if not it fetches alternative albums and looks for the same track.

I tested this with a playlist of mine which has tracks which have now new albums ID's.

With version 2.1.0, I can download 68/95 tracks. With fetching alternatives, I can download 89/95 tracks.

Playlist: https://www.deezer.com/us/playlist/10310080842

Errors without fetching the alternatives:

           ERROR    Persistent error downloading track 'Камикадзе', skipping: Cannot connect to host e-cdns-proxy-0.dzcdn.net:443 ssl:True [SSLCertVerificationError: (1, '[SSL:                    track.py:68
                    CERTIFICATE_VERIFY_FAILED] certificate verify failed: self-signed certificate (_ssl.c:1000)')]
           ERROR    Error downloading track: [Errno 2] No such file or directory: '/home/mandy/StreamripDownloads/Guitar - Drop B/26. Stigmata - Камикадзе.mp3'                                 playlist.py:130
           ERROR    Error downloading track 'Магмель', retrying: Cannot connect to host e-cdns-proxy-1.dzcdn.net:443 ssl:True [SSLCertVerificationError: (1, '[SSL: CERTIFICATE_VERIFY_FAILED]      track.py:52
                    certificate verify failed: self-signed certificate (_ssl.c:1000)')]
           ERROR    Persistent error downloading track 'Магмель', skipping: Cannot connect to host e-cdns-proxy-1.dzcdn.net:443 ssl:True [SSLCertVerificationError: (1, '[SSL:                      track.py:68
                    CERTIFICATE_VERIFY_FAILED] certificate verify failed: self-signed certificate (_ssl.c:1000)')]
           ERROR    Error downloading track: [Errno 2] No such file or directory: '/home/mandy/StreamripDownloads/Guitar - Drop B/29. Stigmata - Магмель.mp3'                                   playlist.py:130
           ERROR    Error downloading track 'At War', retrying: Cannot connect to host e-cdns-proxy-e.dzcdn.net:443 ssl:True [SSLCertVerificationError: (1, '[SSL: CERTIFICATE_VERIFY_FAILED]       track.py:52
                    certificate verify failed: self-signed certificate (_ssl.c:1000)')]

One of the tracks is this on: https://www.deezer.com/us/track/91337844

The album doesn't exist anymore, but the track is still on another album available, with that fix in place:

I can download 93/95 tracks.