Adds Neon Carpet (#55782)

* Adds emissive carpet, adds plane support to decal element

- Adds a basic abstract/debugging emissive carpet
- Makes decals capable of supporting plane
- Adds auto-smoothing decals

* Adds simple neon carpet variations

* Adds neon carpet reagents and recipes

* Refactors emissive blockers to allow multiple layers of emissive / emissive blocking objects

- Splits the emissive and emissive blocker plane masters into several plane masters which handle different layers of emissiveness.

* Makes neon carpet tile stacks emissive

* Rearranges and docs some emissive plane masters

- Folds the overlay lighting plane master into the emissive planes since it is also used to mask the lighting plane

* Fixes null mats_per_unit stack recombining after splitting

- I think I broke this a while ago when I reworked how stacks handle materials. Whoops.
- This basically only effects carpet at the moment. Good thing I did this when I did!

* Adds neon carpets to cargo

- Adds a cargo supply crate containing a _lot_ of neon carpets for 3000 credits

* Fixes neon carpet highlights leaking through vending machines and such

- Turns out vending machines axed their own emissive blockers whenever they updated their icon because they cleared their managed_vis_overlays...
- Generic emissive blocking has been elementized and some update_overlays procs have been straightened out.

* Fixes id_arg_index for the emissive blocker element

* Commits @Rohsie's suggestions

code/game/objects/structures/crates_lockers/closets.dm

@@ -8,6 +8,7 @@
 	max_integrity = 200
 	integrity_failure = 0.25
 	armor = list(MELEE = 20, BULLET = 10, LASER = 10, ENERGY = 0, BOMB = 10, BIO = 0, RAD = 0, FIRE = 70, ACID = 60)
+	blocks_emissive = EMISSIVE_BLOCK_UNIQUE
 
 	var/icon_door = null
 	var/icon_door_override = FALSE //override to have open overlay use icon different to its base's
@@ -71,7 +72,6 @@
 
 /obj/structure/closet/proc/closet_update_overlays(list/new_overlays)
 	. = new_overlays
-	SSvis_overlays.remove_vis_overlay(src, managed_vis_overlays)
 	luminosity = 0
 	if(!opened)
 		if(icon_door)
@@ -83,7 +83,7 @@
 		if(secure && !broken)
 			//Overlay is similar enough for both that we can use the same mask for both
 			luminosity = 1
-			SSvis_overlays.add_vis_overlay(src, icon, "locked", EMISSIVE_LAYER, EMISSIVE_PLANE, dir, alpha)
+			SSvis_overlays.add_vis_overlay(src, icon, "locked", EMISSIVE_STRUCTURE_LAYER, EMISSIVE_STRUCTURE_PLANE, dir, alpha)
 			if(locked)
 				. += "locked"
 			else