Enhances algorithm for finding an atom mount (#94076)

## About The Pull Request
Depends on #94064 for the unit test but offers a better method for
finding an atom to mount on
- Finding a mount now takes into consideration the objects pixel x & y
offsets meaning diagonal mounting is now supported. Gives great
flexibility for mappers
- If you don't want to use pixel offsets but default back to using the
objects direction that behaviour is still preserved. Useful if your
object uses directional icon states(lights & cameras for now) AND don't
use offsets
- If no direction could be specified then as the last resort it defaults
back to the objects local turf for mounting

## Changelog
🆑
fix: all mounted objects on tables, fences, windows & walls should fall
of correctly when the atom it is placed on is destroyed
fix: security telescreen now falls off when their mounted wall is
destroyed
fix: defib wall mount falls off when their mounted wall is destroyed
fix: floor lights are mounted to the ground/catwalk/tram floor they are
sitting on meaning destroying it will destroy the light
fix: wall mounted plaques now fall off when their mounted wall is
destroyed
/🆑

code/modules/power/lighting/light_construct.dm

@@ -30,16 +30,19 @@
 
 /obj/structure/light_construct/Initialize(mapload)
 	. = ..()
-	if(mapload && !find_and_hang_on_atom(mark_for_late_init = TRUE))
+	if(mapload && !find_and_mount_on_atom(mark_for_late_init = TRUE))
 		return INITIALIZE_HINT_LATELOAD
 
 /obj/structure/light_construct/LateInitialize()
-	find_and_hang_on_atom(late_init = TRUE)
+	find_and_mount_on_atom(late_init = TRUE)
 
 /obj/structure/light_construct/Destroy()
 	QDEL_NULL(cell)
 	return ..()
 
+/obj/structure/light_construct/get_turfs_to_mount_on()
+	return list(get_step(src, dir))
+
 /obj/structure/light_construct/get_cell()
 	return cell
 
@@ -150,7 +153,7 @@
 					if("floor")
 						new_light = new /obj/machinery/light/floor/empty(loc)
 				new_light.setDir(dir)
-				new_light.find_and_hang_on_atom()
+				new_light.find_and_mount_on_atom()
 				transfer_fingerprints_to(new_light)
 				if(!QDELETED(cell))
 					new_light.cell = cell