Move MIDI networking logic from content to engine.

[gradientvera]

trafficstars

• Create a generic component for entities that use MIDI renderers, give it networking support.
  • The current SS14 InstrumentComponent would simply add any content-specific logic needed, such as program change restrictions, forced program/bank, stun user on MIDI limit violation...
• Create a simple way to network MIDI without using entities. Useful in content for admin MIDIs, etc.