Allows creating new areas on the tram asteroid and surrounding mini-asteroids (#80260)

## About The Pull Request

Exactly what it says on the tin.

## Why It's Good For The Game

Allows people to expand rooms into the asteroid, or create new rooms
within it.

## Changelog

🆑
qol: The asteroid on Tramstation can now have areas expanded into or
created within.
/🆑

code/__HELPERS/areas.dm

@@ -86,6 +86,7 @@ GLOBAL_LIST_INIT(typecache_powerfailure_safe_areas, typecacheof(/area/station/en
 	// Ignore these areas and dont let people expand them. They can expand into them though
 	var/static/list/blacklisted_areas = typecacheof(list(
 		/area/space,
+		/area/station/asteroid,
 		))
 
 	var/error = ""

code/game/area/areas/station/misc.dm

@@ -31,3 +31,4 @@
 	requires_power = TRUE
 	ambience_index = AMBIENCE_MINING
 	area_flags = UNIQUE_AREA
+	outdoors = TRUE