UI: option not to show screen splitting widgets

Request for simplified Blender template,
this may be extended to limit access to other UI changes
that could be pressed by accident.

release/scripts/startup/bl_ui/space_userpref.py

@@ -316,6 +316,9 @@ class USERPREF_PT_interface(Panel):
         col.separator()
         col.separator()
 
+        col.label(text="Screen:")
+        col.prop(view, "show_layout_ui")
+
         col.prop(view, "show_splash")