abstraction: move object under abstraction

alib2common/src/object/Object.h → alib2abstraction/src/object/Object.h

 #pragma once
-#include <alib/variant>
+#include <ext/variant>
 #include <object/AnyObject.h>
 namespace object {

alib2common/src/object/Void.cpp

-#include "Void.h"
-#include "Object.h"
+#include <object/Void.h>
+#include <object/Object.h>
 #include <registration/ValuePrinterRegistration.hpp>
 namespace object {