Support MIDI Output

[danngreen]

To map MIDI outputs on VCV, use a similar concept to the MIDI Input mapping (using the Core MIDI modules).

Also would extend the Add MIDI Connection feature in firmware (not yet merged into master as of this post)

On the backend, we would need to extend the Params data structure for the additional MIDI event stream. The M4 Controls could parse the events and send MIDI using the existing drivers.