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/controllers/configuration/configuration.dm

@@ -236,7 +236,7 @@
 
 		switch (command)
 			if ("map")
-				currentmap = new ("_maps/[data].json")
+				currentmap = load_map_config("_maps/[data].json")
 				if(currentmap.defaulted)
 					log_config("Failed to load map config for [data]!")
 					currentmap = null