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/modules/mapping/space_management/space_level.dm

@@ -1,5 +1,5 @@
 /datum/space_level
-	var/name = "Your config settings failed, you need to fix this for the datum space levels to work"
+	var/name = "NAME MISSING"
 	var/list/neigbours = list()
 	var/list/traits
 	var/z_value = 1 //actual z placement
@@ -7,8 +7,8 @@
 	var/xi
 	var/yi   //imaginary placements on the grid
 
-/datum/space_level/New(new_z, new_name, new_linkage = SELFLOOPING, list/new_traits = list())
+/datum/space_level/New(new_z, new_name, list/new_traits = list())
 	z_value = new_z
 	name = new_name
 	traits = new_traits
-	set_linkage(new_linkage)
+	set_linkage(new_traits[ZTRAIT_LINKAGE])