Cleanup: Correct location of node function declarations

Currently there are many function declarations in `BKE_node.h` that
don't actually have implementations in blenkernel. This commit moves
the declarations to `NOD_composite.h`, `NOD_texture.h`, and
`NOD_shader.h` instead. This helps to clarify the purpose of the
different modules.

Differential Revision: https://developer.blender.org/D13869

source/blender/compositor/operations/COM_TextureOperation.cc

@@ -22,6 +22,8 @@
 #include "BKE_image.h"
 #include "BKE_node.h"
 
+#include "NOD_texture.h"
+
 namespace blender::compositor {
 
 TextureBaseOperation::TextureBaseOperation()