Overhauls the entrance to Engineering on PubbyStation to allow for better access control, makes techfab accessible to Atmos. (#48036)

* Overhauls the entrance to PubbyStation's Engineering department to allow for better access control.

* Reset

* I think I fixed it!

* Converts lobby to its own area with its own APC

code/game/area/Space_Station_13_areas.dm

@@ -490,6 +490,10 @@ NOTE: there are two lists of areas in the end of this file: centcom and station
 	name = "Engine Room"
 	icon_state = "atmos_engine"
 
+/area/engine/lobby
+	name = "Engineering Lobby"
+	icon_state = "engi_lobby"
+
 /area/engine/engine_room/external
 	name = "Supermatter External Access"
 	icon_state = "engine_foyer"