Move push to talk bindings to overlaycontroller

The old system used the old OpenVR input system which is
incompatible with the new IVRInput.

This change broke the AccessbilityTabController, but
that is to be removed because the functionality can be
found elsewhere.

src/tabcontrollers/PttController.h

@@ -75,10 +75,7 @@ protected:
     virtual void onPttStop(){};
     virtual void onPttEnabled(){};
     virtual void onPttDisabled(){};
-    virtual bool pttChangeValid()
-    {
-        return true;
-    }
+
     virtual vr::VROverlayHandle_t getNotificationOverlayHandle()
     {
         return vr::k_ulOverlayHandleInvalid;
@@ -100,6 +97,11 @@ public:
     void savePttProfiles();
     void savePttConfig();
 
+    virtual bool pttChangeValid()
+    {
+        return true;
+    }
+
     Q_INVOKABLE QVariantList pttDigitalButtons( unsigned controller );
     Q_INVOKABLE unsigned long pttDigitalButtonMask( unsigned controller );
     Q_INVOKABLE unsigned pttTouchpadMode( unsigned controller );