Cleanup: Move BKE_node.h to C++

See: https://projects.blender.org/blender/blender/issues/103343

Changes:
1. Added `BKE_node.hh` file. New file includes old one.
2. Functions moved to new file. Redundant `(void)`, `struct` are removed.
3. All cpp includes replaced from `.h` on `.hh`.
4. Everything in `BKE_node.hh` is on `blender::bke` namespace.
5. All implementation functions moved in namespace.
6. Function names (`BKE_node_*`) changed to `blender::bke::node_*`.
7. `eNodeSizePreset` now is a class, with renamed items.

Pull Request: https://projects.blender.org/blender/blender/pulls/107790

source/blender/nodes/function/node_function_util.hh

@@ -11,7 +11,7 @@
 
 #include "DNA_node_types.h"
 
-#include "BKE_node.h"
+#include "BKE_node.hh"
 
 #include "BLT_translation.h"