Add wxWithImages::SetImages() and update wxMSW wxNotebook for it

This new function will allow selecting the bitmap of the most suitable
size and automatically react to DPI scale changes (although this hasn't
been implemented yet) in all controls using image lists.

For now, only wxNotebook in wxMSW has been updated to work with it, the
other classes and ports will be updated to override OnImagesChanged()
instead of SetImageList() later.

Also update the notebook sample to use SetImages() rather than
SetImageList() -- which means that it doesn't show the icons any longer
in non-MSW ports, which haven't been updated yet.

samples/notebook/notebook.h

@@ -131,7 +131,7 @@ private:
 
     wxBoxSizer *m_sizerFrame;
 
-    wxImageList *m_imageList;
+    wxBookCtrlBase::Images m_images;
 
     wxDECLARE_EVENT_TABLE();
 };