Add YAML creation tooling

[mdwn]

Creating the YAML files is burdensome. We should add tooling to ease the pain of generating these.

[mdwn]

The more I think about this, the more I think that the current YAML format for songs is a little cumbersome in general. I wonder if we can come up with a slimmer version, or potentially introduce some sort of custom language that we can use either as a field in the YAML or to replace the YAML entirely.