[Companion] Show custom control names throughout the UI (& internal refactoring) (#4693)

* [Companion] Introduce new Boards class to further consolidate hardware metadata and remove some globals.

* [Companion] * RawSource::toString() and RawSwitch::toString() can now return custom hardware names (if given a GeneralSettings object) for the following types (respectively):
    SOURCE_TYPE_STICK, SOURCE_TYPE_SWITCH, SWITCH_TYPE_SWITCH, & SWITCH_TYPE_MULTIPOS_POT;
* RawSource::isPot() and isSlider() can now return their own index position in potConfig[]/sliderConfig[];
* Switch indicator strings can be localized if necessary.

* [Companion] Refactor model printers to use new RawSource/RawSwitch capabilities; Simplify model-to-printer mapping scheme in multimodelprinter; Use const ModelData pointer.

* [Companion] Refactor how RawSource and RawSwitch selection combo boxes are populated, using cache-able data models instead of direct manipulation; Refactor some other Helpers function into their own namespace.

* Cosmetics & forgotten qualifier.

radio/src/targets/simu/opentxsimulator.cpp

@@ -134,7 +134,7 @@ void OpenTxSimulator::getTrims(Trims & trims)
 {
   uint8_t phase = getFlightMode();
   trims.extended = hasExtendedTrims();
-  for (uint8_t idx=0; idx < CPN_MAX_STICKS + CPN_MAX_AUX_TRIMS; idx++) {
+  for (uint8_t idx=0; idx < CPN_MAX_TRIMS; idx++) {
     trims.values[idx] = getTrimValue(getTrimFlightMode(phase, idx), idx);
   }