Merge pull request #21182 from mshabunin:split-cv2cpp

Split cv2.cpp

* split cv2.cpp: util, numpy

* split cv2.cpp: convert

* split cv2.cpp: highgui, more utils

* split cv2.cpp: fix numpy import

modules/python/src2/cv2_highgui.hpp

@@ -0,0 +1,14 @@
+#ifndef CV2_HIGHGUI_HPP
+#define CV2_HIGHGUI_HPP
+
+#include "cv2.hpp"
+#include "opencv2/opencv_modules.hpp"
+
+#ifdef HAVE_OPENCV_HIGHGUI
+PyObject *pycvSetMouseCallback(PyObject*, PyObject *args, PyObject *kw);
+// workaround for #20408, use nullptr, set value later
+PyObject *pycvCreateTrackbar(PyObject*, PyObject *args);
+PyObject *pycvCreateButton(PyObject*, PyObject *args, PyObject *kw);
+#endif
+
+#endif // CV2_HIGHGUI_HPP