Figure out how to move away from huge custom seeder

[samuelhorwitz]

See #124 and all related. Basically, our main seeder is 10k tracks I threw together early in the beginning. I consistently find garbage I accidentally put into it that ruins trance playlists. However, some classics simply don't exist in the label-driven playlists I want to move to.

I need to come up with a solution to prune my seeder down to something reasonable and try to find other playlists to rely on for some of it. The goal should be cleaning it up of cruft/non-trance and offloading as much playlist management as possible.