scene_tree.h
Pre-requisite before removing `scene_tree.h` from `node.h` which has cascading consequences on most of the codebase.
callable_method_pointer.h
callable_mp.h
This allows removing it from `class_db.h`, significantly reducing the amount of files that include it transitively. Also includes some include cleanup in `control.h` and `rich_text_label.h` done while ensure they don't depend on `callable_mp`.
• Excludes module tests, as they'd be a more involved process