Implement beta IVRInput system for testing

In order to test new system:

Build and deploy application.

Copy both files from IVRInput/ dir into the bin/win64 folder.

Change const std::string m_actionManifestPath in steamivrinput.h to be
directly to your action_manifest.json file.

Run and turn on a Vive controller. Press the menu button. If logs say
"NEXT SONG SET!" it works.

src/overlaycontroller.h

@@ -39,6 +39,8 @@
 #include "tabcontrollers/UtilitiesTabController.h"
 #include "tabcontrollers/AccessibilityTabController.h"
 
+#include "steamivrinput.h"
+
 // application namespace
 namespace advsettings
 {
@@ -90,6 +92,7 @@ private:
 
 public: // I know it's an ugly hack to make them public to enable external
         // access, but I am too lazy to implement getters.
+    SteamIVRInput m_actions;
     SteamVRTabController m_steamVRTabController;
     ChaperoneTabController m_chaperoneTabController;
     MoveCenterTabController m_moveCenterTabController;