TD: [skip ci] activate PCH of TechDraw (Gui) and use forward declarations

For MSVC this reduces compile time by ~20%

src/Mod/TechDraw/Gui/ViewProviderAnnotation.cpp

@@ -29,6 +29,7 @@
 
 #include <App/DocumentObject.h>
 #include "ViewProviderAnnotation.h"
+#include "QGIView.h"
 
 using namespace TechDrawGui;