Cleanup: Move several blenkernel headers to C++

Mostly focus on areas where we're already using C++ features,
where combining C and C++ APIs is getting in the way.

Pull Request: https://projects.blender.org/blender/blender/pulls/114972

source/blender/python/intern/bpy_interface.cc

@@ -44,7 +44,7 @@
 #include "DNA_text_types.h"
 
 #include "BKE_appdir.h"
-#include "BKE_context.h"
+#include "BKE_context.hh"
 #include "BKE_global.h" /* Only for script checking. */
 #include "BKE_main.h"
 #include "BKE_text.h"