QtSupport et al: Move QtVersionFactory to *QtVersion implementation

At most a dozen lines each left.

Change-Id: Ifbf34f814266ba7bee83d3fee9db831eb450dfc4
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>

src/plugins/android/androidqtversion.h

@@ -26,6 +26,7 @@
 #pragma once
 
 #include <qtsupport/baseqtversion.h>
+#include <qtsupport/qtversionfactory.h>
 
 #include <QCoreApplication>
 
@@ -62,5 +63,11 @@ private:
     mutable int m_minNdk = -1;
 };
 
+class AndroidQtVersionFactory : public QtSupport::QtVersionFactory
+{
+public:
+    AndroidQtVersionFactory();
+};
+
 } // namespace Internal
 } // namespace Android