MIDI: Add MidiUmpDeviceService

This CL allows apps to expose a virtual UMP MIDI device.

MidiDeviceService existed before and MidiUmpDeviceService acts
similarly. The main change between the services is that apps now
expose ports instead of inputs and outputs. This is due to UMP being
bidirectional.

Bug: 291115176
Test: MidiEchoTest
Change-Id: If2370420dd758287a90abfac7b12f6b3087c82e3