qt: add option to disable controller applet

- add checkbox to disable the controller applet UI
- when controller applet is disabled, use the yuzu-cmd fallback
  controller applet that applies controller config based on rules
- See https://github.com/yuzu-emu/yuzu/issues/8552 for some discussion

src/yuzu/main.cpp

@@ -1562,6 +1562,7 @@ bool GMainWindow::LoadROM(const QString& filename, u64 program_id, std::size_t p
 
     system->SetAppletFrontendSet({
         std::make_unique<QtAmiiboSettings>(*this),     // Amiibo Settings
+        (UISettings::values.controller_applet_disabled.GetValue() == true) ? nullptr :
         std::make_unique<QtControllerSelector>(*this), // Controller Selector
         std::make_unique<QtErrorDisplay>(*this),       // Error Display
         nullptr,                                       // Mii Editor