qt/hotkey: Get rid of global hotkey map instance

Instead, we make a proper registry class and house it within the main
window, then pass it to whatever needs access to the loaded hotkeys.

This way, we avoid a global variable, and don't need to initialize a
std::map instance before the program can do anything.

src/yuzu/configuration/configure_general.cpp

@@ -35,6 +35,10 @@ void ConfigureGeneral::setConfiguration() {
     ui->use_docked_mode->setChecked(Settings::values.use_docked_mode);
 }
 
+void ConfigureGeneral::PopulateHotkeyList(const HotkeyRegistry& registry) {
+    ui->widget->Populate(registry);
+}
+
 void ConfigureGeneral::applyConfiguration() {
     UISettings::values.gamedir_deepscan = ui->toggle_deepscan->isChecked();
     UISettings::values.confirm_before_closing = ui->toggle_check_exit->isChecked();