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/game/objects/structures/detectiveboard.dm

@@ -34,7 +34,7 @@ MAPPING_DIRECTIONAL_HELPERS(/obj/structure/detectiveboard, 32)
 			if(istype(item, /obj/item/paper) || istype(item, /obj/item/photo))
 				item.forceMove(src)
 				cases[current_case].notices++
-		find_and_hang_on_atom()
+		find_and_mount_on_atom()
 
 	register_context()
 

code/game/objects/structures/extinguisher.dm

@@ -18,7 +18,7 @@ MAPPING_DIRECTIONAL_HELPERS(/obj/structure/extinguisher_cabinet, 29)
 		opened = TRUE
 	else
 		stored_extinguisher = new /obj/item/extinguisher(src)
-		find_and_hang_on_atom()
+		find_and_mount_on_atom()
 	update_appearance(UPDATE_ICON)
 	register_context()
 

code/game/objects/structures/fireaxe.dm

@@ -39,7 +39,7 @@ MAPPING_DIRECTIONAL_HELPERS(/obj/structure/fireaxecabinet, 32)
 		held_item = new item_path(src)
 	update_appearance()
 	if(mapload)
-		find_and_hang_on_atom()
+		find_and_mount_on_atom()
 
 /obj/structure/fireaxecabinet/Destroy()
 	if(held_item)

code/game/objects/structures/mirror.dm

@@ -55,7 +55,7 @@
 		check_reflect_signals = list(SIGNAL_ADDTRAIT(TRAIT_NO_MIRROR_REFLECTION), SIGNAL_REMOVETRAIT(TRAIT_NO_MIRROR_REFLECTION)), \
 	)
 	if(mapload)
-		find_and_hang_on_atom()
+		find_and_mount_on_atom()
 	update_choices()
 	register_context()
 

code/game/objects/structures/noticeboard.dm

@@ -36,7 +36,7 @@ MAPPING_DIRECTIONAL_HELPERS(/obj/structure/noticeboard, 32)
 		notices++
 	update_appearance(UPDATE_ICON)
 	if(mapload)
-		find_and_hang_on_atom()
+		find_and_mount_on_atom()
 
 //attaching papers!!
 /obj/structure/noticeboard/attackby(obj/item/O, mob/user, list/modifiers, list/attack_modifiers)

code/game/objects/structures/plaques/_plaques.dm

@@ -20,6 +20,8 @@
 
 /obj/structure/plaque/Initialize(mapload)
 	. = ..()
+	if(mapload)
+		find_and_mount_on_atom()
 	register_context()
 
 /obj/structure/plaque/add_context(atom/source, list/context, obj/item/held_item, mob/user)

code/game/objects/structures/plaques/static_plaques.dm

@@ -9,6 +9,13 @@
 		SET_PLANE_IMPLICIT(src, FLOOR_PLANE)
 		layer = HIGH_TURF_LAYER
 
+/obj/structure/plaque/static_plaque/get_moutable_objects()
+	return list()
+
+/obj/structure/plaque/static_plaque/find_and_mount_on_atom(mark_for_late_init, late_init)
+	if(isProbablyWallMounted(src))
+		return ..()
+
 /obj/structure/plaque/static_plaque/atmos
 	name = "\improper FEA Atmospherics Division plaque"
 	desc = "This plaque commemorates the fall of the Atmos FEA division. For all the charred, dizzy, and brittle men who have died in its hands."

code/game/objects/structures/secure_safe.dm

@@ -107,10 +107,10 @@ MAPPING_DIRECTIONAL_HELPERS(/obj/structure/secure_safe, 32)
 	AddComponent(/datum/component/lockable_storage, stored_lock_code)
 	if(mapload)
 		PopulateContents()
-		find_and_hang_on_atom()
+		find_and_mount_on_atom()
 	RegisterSignal(src, COMSIG_LOCKABLE_STORAGE_SET_CODE, PROC_REF(update_lock_code))
 
-/obj/structure/secure_safe/find_and_hang_on_atom(mark_for_late_init = FALSE, late_init = FALSE)
+/obj/structure/secure_safe/find_and_mount_on_atom(mark_for_late_init, late_init)
 	if(!density)
 		return ..()
 

code/game/objects/structures/signs/_signs.dm

@@ -23,11 +23,11 @@
 /obj/structure/sign/Initialize(mapload)
 	. = ..()
 	register_context()
-	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/sign/LateInitialize()
-	find_and_hang_on_atom(late_init = TRUE)
+	find_and_mount_on_atom(late_init = TRUE)
 
 /obj/structure/sign/add_context(atom/source, list/context, obj/item/held_item, mob/user)
 	. = ..()
@@ -220,7 +220,7 @@
 	playsound(target_turf, 'sound/items/deconstruct.ogg', 50, TRUE)
 	placed_sign.update_integrity(get_integrity())
 	placed_sign.setDir(dir)
-	placed_sign.find_and_hang_on_atom()
+	placed_sign.find_and_mount_on_atom()
 	qdel(src)
 	return ITEM_INTERACT_SUCCESS
 

code/game/objects/structures/water_structures/urinal.dm

@@ -16,7 +16,7 @@ MAPPING_DIRECTIONAL_HELPERS(/obj/structure/urinal, 32)
 	. = ..()
 	if(mapload)
 		hidden_item = new /obj/item/food/urinalcake(src)
-		find_and_hang_on_atom()
+		find_and_mount_on_atom()
 
 /obj/structure/urinal/Exited(atom/movable/gone, direction)
 	. = ..()