Extracting and re-packaging some components from @magenta/music

[sebs]

I really like some aspects of the implementations around midi, soundfonts etc and thought about extracting them to a web component base with a smaller dependency footprint. Some of the fundamentals are just to well written, so I would copy verbatim in a way anyway if I set out to do it the same way.

Some questions

• where would you start (i figured soundfonts are a good entry point)
• not sure about the standards. Seems parsers for the formats are still in demand? this the reason to go through json definition?

Ill take any ideas ;)