Observers can auto-orbit meteors; space dust event (#19142)

* Observers can auto-orbit meteors; space dust event

During a meteor shower, observers can automatically orbit
threatening meteors and watch them hit the station.

Added Major Space Dust event, which is a meteor shower
containing only space dust.

Reduced chance of RNG meteor event.

Fixes bug where meteors wouldn't move when spawned.

code/modules/mining/mine_turfs.dm

@@ -487,11 +487,10 @@
 		if(3)
 			return
 		if(2)
-			if (prob(20))
+			if(prob(20))
 				src.gets_dug()
 		if(1)
 			src.gets_dug()
-	return
 
 /turf/open/floor/plating/asteroid/attackby(obj/item/weapon/W, mob/user, params)
 	//note that this proc does not call ..()