ACTION-33: MIDI charter proposal

My goal in proposing a MIDI API was to provide the web platform's analog to
CoreMIDI on MacOS/iOS, or the Windows MIDI api.  Here's a proposal for
charter proposal text:

MIDI Device Communication

Some user agents have connected music devices, such as synthesizers,
keyboard controllers and drum machines.  The widely adopted MIDI
protocol enables electronic musical instruments, controllers and computers
to communicate and synchronize with each other. MIDI does not transmit
audio signals: instead, it sends event messages about musical notes,
controller signals for parameters such as volume, vibrato and panning, cues
and clock signals to set the tempo, and system-specific MIDI communications
(e.g. to remotely store synthesizer-specific patch data).  Additionally,
MIDI has become a standard for show control, lighting and special effects
control.

This deliverable defines an API supporting the MIDI protocol and MIDI
device input and output selection.  This API should be defined at such a
level as to enable non-music MIDI applications as well as music ones.


-Chris