As part of T75724, many UI layouts are now coded inside large modules (nodes, modifiers, etc).
This has the disadvantage of these modules depending on /editors for simple high-level button code.

An example of this can be seen in rBcfa48c84d06ca8197f86b6d3ceef8a2c7c311a82

A possible solution to this is moving some high-level UI code from editors in its own UI module.

Candidates for such a change are:

UI_icons.h
UI_interface_icons.h
UI_interface.h
UI_resources.h
UI_view2d.h
... possible others

Some files editor code should be moved to UI_:

ED_screen.h --> UI_screen.h
ED_gizmo_library.h --> UI_gizmo_library.h
ED_gizmo_utils.h --> UI_gizmo_utils.h

This task is first meant to gauge if this is something we should do. After then we can move more into the how.