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/citra_qt/configuration/configure_general.cpp

@@ -56,6 +56,10 @@ void ConfigureGeneral::setConfiguration() {
         ui->language_combobox->findData(UISettings::values.language));
 }
 
+void ConfigureGeneral::PopulateHotkeyList(const HotkeyRegistry& registry) {
+    ui->hotkeysDialog->Populate(registry);
+}
+
 void ConfigureGeneral::applyConfiguration() {
     UISettings::values.confirm_before_closing = ui->toggle_check_exit->isChecked();
     UISettings::values.theme =