Database seeds

[beer-psi]

Having to ssh into the server to update chart constants and other metadata is a pain. This also prevents other people from self-hosting the bot to its full potential, since they still have to retrieve song/chart information on their own.

Ideally, database seeds for songs, charts, aliases, etc. should be stored in the repository, and synced to the official instance when there is an update, similar to what https://github.com/TNG-dev/Tachi does.