New class ModelConfig wrapping DynamicPrintConfig and a timestamp

to help with detecting "not changed" event when taking
Undo/Redo snapshot or synchronizing with the back-end.

Converted layer height profile and supports / seam painted areas
to the same timestamp controlled structure.

src/slic3r/GUI/ConfigManipulation.cpp

@@ -2,6 +2,7 @@
 #include "ConfigManipulation.hpp"
 #include "I18N.hpp"
 #include "GUI_App.hpp"
+#include "libslic3r/Model.hpp"
 #include "libslic3r/PresetBundle.hpp"
 
 #include <wx/msgdlg.h>