Add "ID" and "SQ" mode visualisations to GNC255

[tigert]

The Garmin GNC255 lets you monitor the morse code of the tuned nav radio station by pressing the Nav volume knob.

• Add message type to set ID mode on
• visualize the setting with a "ID" as in the photo below

Similarly the COM radio volume push toggles "SQ" display for the noise gate squelch setting. This is not simulated in either MSFS and X-Plane radios, but we should include it for completeness. One could set autohotkey to play a static hiss on the background for a pretty viable simulation if one wants, but in any case the functionality of showing "SQ" on screen would be good to add, even though the NAV ID mode actually works too.

I am filing these so I will not forget these, and in case someone feels like arduino hacking and is looking for some hacking to do.