Feature Request: Add MPU-401 MIDI output support

[SuperSodaSea]

Recently I tried to run Omniscent in js-dos and found that it worked quite well, except there is no sound output.

This program use MPU-401 MIDI output which is supported in DOSBox, but js-dos doesn't seem to support it.

This feature could be implemented with Web MIDI API, or packages like webmidi or jzz (which have a jzz-synth-tiny that can simulate MIDI). Or maybe we can just provide an interface that users can make plugins to implement it.

I'm willing to work on this feature. If anyone can tell me where is a good place to start implementing this feature, I would appreciate it.

[caiiiycuk]

Not sure, but probably it will be supported by dosbox-x backend that I develop now