[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.

companion/src/printdialog.cpp

@@ -36,7 +36,7 @@ PrintDialog::PrintDialog(QWidget *parent, Firmware * firmware, GeneralSettings &
   ui->setupUi(this);
   setWindowIcon(CompanionIcon("print.png"));
   setWindowTitle(model.name);
-  multimodelprinter.setModel(0, model);
+  multimodelprinter.setModel(0, model, generalSettings);
   ui->textEdit->setHtml(multimodelprinter.print(ui->textEdit->document()));
   if (!printfilename.isEmpty()) {
     printToFile();
@@ -44,7 +44,7 @@ PrintDialog::PrintDialog(QWidget *parent, Firmware * firmware, GeneralSettings &
   }
 }
 
-void PrintDialog::closeEvent(QCloseEvent *event) 
+void PrintDialog::closeEvent(QCloseEvent *event)
 {
 }