Extract editor run toolbar into its own component

- Simplify and update its logic.
- Simplify EditorScript.
- Improve EditorNode and other relevant includes.
- Fix scene-based path in the movie writer when
reloading a scene.

modules/gltf/editor/editor_scene_exporter_gltf_plugin.cpp

@@ -37,6 +37,7 @@
 #include "editor/editor_file_system.h"
 #include "editor/editor_node.h"
 #include "editor/gui/editor_file_dialog.h"
+#include "scene/gui/popup_menu.h"
 
 String SceneExporterGLTFPlugin::get_name() const {
 	return "ConvertGLTF2";