Support stations with multiple z-levels (#35339)

* Remove ZLEVEL_STATION_PRIMARY

* Add Up and Down traits for use by ladders and chasms

* Give map_config creation its own proc

* Combine LoadConfig and ValidateJSON and remove transition_config

* Make space linkage a z-level trait

* Remove ZLEVEL_EMPTY_SPACE

* Update uses of GetFullMapPath

* Handle multi-Z stations and load Lavaland and Reebe at runtime

* Remove unused space maps

* Fix inappropriate z-expansion in map reader, improve logging

* Update comments relating to z-level configuration

* Add Lavaland and Reebe to ALL_MAPS

code/game/turfs/simulated/chasm.dm

@@ -11,7 +11,7 @@
 
 /turf/open/chasm/Initialize()
 	. = ..()
-	AddComponent(/datum/component/chasm, null)
+	AddComponent(/datum/component/chasm, SSmapping.get_turf_below(src))
 
 /turf/open/chasm/proc/set_target(turf/target)
 	GET_COMPONENT(chasm_component, /datum/component/chasm)
@@ -64,16 +64,6 @@
 /turf/open/chasm/CanPass(atom/movable/mover, turf/target)
 	return 1
 
-
-// Naive "down" which just subtracts a z-level
-/turf/open/chasm/straight_down
-	baseturfs = /turf/open/chasm/straight_down
-
-/turf/open/chasm/straight_down/Initialize()
-	. = ..()
-	set_target(locate(x, y, z - 1))
-
-
 // Chasms for Lavaland, with planetary atmos and lava glow
 /turf/open/chasm/lavaland
 	initial_gas_mix = LAVALAND_DEFAULT_ATMOS
@@ -95,10 +85,3 @@
 	underlay_appearance.icon = 'icons/turf/floors.dmi'
 	underlay_appearance.icon_state = "dirt"
 	return TRUE
-
-/turf/open/chasm/jungle/straight_down
-	baseturfs = /turf/open/chasm/jungle/straight_down
-
-/turf/open/chasm/jungle/straight_down/Initialize(mapload)
-	. = ..()
-	set_target(locate(x, y, z - 1))

code/game/turfs/simulated/floor/plating/dirt.dm

@@ -3,7 +3,7 @@
 	desc = "Upon closer examination, it's still dirt."
 	icon = 'icons/turf/floors.dmi'
 	icon_state = "dirt"
-	baseturfs = /turf/open/chasm/jungle/straight_down
+	baseturfs = /turf/open/chasm/jungle
 	initial_gas_mix = LAVALAND_DEFAULT_ATMOS
 	planetary_atmos = TRUE
 	attachment_holes = FALSE