Allow setting a default timbrality mode for new devices

[BenMcLean]

Is your feature request related to a problem? Please describe.
When I plug in a new device, my brain just expects it to always act like the "MULTI" timbrality mode. Maybe I'm just inexperienced but it just seems like that's how MIDI is supposed to work. Several times I'll check only to discover it's in "ACTI" mode when I didn't expect it to be, so I'll get weird stuff happening like getting the wrong instrument to play when I press the keys on my MIDI controller or worse, no instrument.

Describe the solution you'd like
I would suggest having an option in the Admin menu for what the default timbrality mode should be for new devices. That way, I could set it to "MULTI" and then forget it because all my MIDI devices would then always act the way I'd expect.

Describe alternatives you've considered
If not in the Admin menu then somewhere else maybe.

Additional context
I keep plugging things in and then getting confused when they don't act like "MULTI" and it turns out they are defaulting to "ACTI" timbrality mode.

[riban-bw]

This needs a setting in zynmidirouter which is where the input devices are configured.