[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/kernel/xam/xam_module.h

@@ -20,9 +20,6 @@ namespace xe {
 namespace kernel {
 namespace xam {
 
-bool xeXamIsUIActive();
-bool xeXamIsNuiUIActive();
-
 static constexpr std::string_view kXamModuleLoaderDataFileName =
     "launch_data.bin";