Ports a large chunk of the map datum system that europa/bay uses.

Links many map-specific details such as the station name, z-level information, and allowed jobs from global vars to map datum vars, which should help us maintain multiple maps at once in the future, which will be needed for the future Southern Cross.
Note that a config change will be needed to change GENERATE_ASTEROID to GENERATE_MAP, otherwise no changes should be required to continue normal map usage.
To change to a different map, it's suggested to tick the file that ticks all the other needed files, which for the Northern Star is called northern_star.dm.

code/game/periodic_news.dm

@@ -6,9 +6,13 @@
 		round_time // time of the round at which this should be announced, in seconds
 		message // body of the message
 		author = "NanoTrasen Editor"
-		channel_name = "The "+starsys_name+" Times"
 		can_be_redacted = 0
 		message_type = "Story"
+		channel_name = null
+
+	New() // I'm sorry...
+		..()
+		channel_name = "The [using_map.starsys_name] Times"
 
 	revolution_inciting_event
 
@@ -66,7 +70,6 @@
 			round_time = 60 * 50
 
 		found_ssd
-			channel_name = "The "+starsys_name+" Times"
 			author = "Doctor Eric Hanfield"
 
 			message = {"Several people have been found unconscious at their terminals. It is thought that it was due
@@ -78,7 +81,6 @@
 	lotus_tree
 
 		explosions
-			channel_name = "The "+starsys_name+" Times"
 			author = "Reporter Leland H. Howards"
 
 			message = {"The newly-christened civillian transport Lotus Tree suffered two very large explosions near the
@@ -92,9 +94,7 @@
 	food_riots
 
 		breaking_news
-			channel_name = "The "+starsys_name+" Times"
 			author = "Reporter Ro'kii Ar-Raqis"
-
 			message = {"Breaking news: Food riots have broken out throughout the Refuge asteroid colony in the Tenebrae
 						Lupus system. This comes only hours after NanoTrasen officials announced they will no longer trade with the
 						colony, citing the increased presence of \"hostile factions\" on the colony has made trade too dangerous to
@@ -103,9 +103,7 @@
 			round_time = 60 * 10
 
 		more
-			channel_name = "The "+starsys_name+" Times"
 			author = "Reporter Ro'kii Ar-Raqis"
-
 			message = {"More on the Refuge food riots: The Refuge Council has condemned NanoTrasen's withdrawal from
 			the colony, claiming \"there has been no increase in anti-NanoTrasen activity\", and \"\[the only] reason
 			NanoTrasen withdrew was because the \[Tenebrae Lupus] system's Phoron deposits have been completely mined out.