Changes cargo defines (STOCK_ITEM_*) to fix a deep recursion (and eventual runtime) issue (#10465)

The defines now create a subtype under cargo_master for every spawner
proc and use that to define probability and register the spawner instead
of making tons of proc overrides.

This also allows for more flexibility when defining the spawners if
desired.

code/controllers/subsystems/initialization/misc_early.dm

@@ -44,6 +44,6 @@
 		ore_data[OD.name] = OD
 
 	// Setup cargo spawn lists.
-	global.cargo_master.setup_cargo_stock()
+	setup_cargo_spawn_lists()
 
 	..()