[UI] Add simple support for controller usage in UI

- Disabled unnecessary hotkeys thread when it is not used
- Removed problematic xam_exports static initialization
- Moved xam_dialogs_shown_ and xam_nui_dialogs_shown_ to XamState

src/xenia/emulator.cc

@@ -279,10 +279,7 @@ X_STATUS Emulator::Setup(
   if (input_driver_factory) {
     auto input_drivers = input_driver_factory(display_window_);
     for (size_t i = 0; i < input_drivers.size(); ++i) {
-      auto& input_driver = input_drivers[i];
-      input_driver->set_is_active_callback(
-          []() -> bool { return !xe::kernel::xam::xeXamIsUIActive(); });
-      input_system_->AddDriver(std::move(input_driver));
+      input_system_->AddDriver(std::move(input_drivers[i]));
     }
   }
 
@@ -291,6 +288,9 @@ X_STATUS Emulator::Setup(
     return result;
   }
 
+  // Add inputSystem to UI
+  imgui_drawer_->LoadInputSystem(input_system_.get());
+
   XELOGI("{}: Initializing VFS...", __func__);
   // Bring up the virtual filesystem used by the kernel.
   file_system_ = std::make_unique<xe::vfs::VirtualFileSystem>();