Improve UX with MIDI I/O backend

[harryhaaren]

Currently, MIDI I/O must be connected using the OS provided infrastructure (eg: ALSA MIDI conncetions) to have MIDI events from a device be routed to the Ctlra created virtual MIDI ports for the device driver. It would be nice to avoid this "extra step" from a UX POV, and simplify it.

One option is to create attach RAW to an existing MIDI I/O port (which the OS creates for the HW), other options include writing a USB MIDI Class Compliant backend for Ctlra.