Restores Northstar's shuttles to the codebase (#89423)

## About The Pull Request
Puts Northstar's shuttles and docks back into the code. This allows for
Northstar to be loaded by admins.

## Why It's Good For The Game

Per Maurukas, shuttles should stay in the code.


![image](https://github.com/user-attachments/assets/87b80dbc-e8e1-43e4-a776-d5c0e4b460a7)


![image](https://github.com/user-attachments/assets/e4a9f03d-be12-49b5-8d1b-ad7ceeadb10f)

## Changelog

Nothing player facing.

code/modules/mining/mine_items.dm

@@ -135,6 +135,10 @@
 	roundstart_template = /datum/map_template/shuttle/mining/kilo
 	height = 10
 
+/obj/docking_port/stationary/mining_home/northstar
+	roundstart_template = /datum/map_template/shuttle/mining/northstar
+	height = 6
+
 /obj/docking_port/stationary/mining_home/nebula
 	roundstart_template = /datum/map_template/shuttle/mining/nebula
 	height = 10
@@ -147,6 +151,9 @@
 /obj/docking_port/stationary/mining_home/common/kilo
 	roundstart_template = /datum/map_template/shuttle/mining_common/kilo
 
+/obj/docking_port/stationary/mining_home/common/northstar
+	roundstart_template = /datum/map_template/shuttle/mining_common/northstar
+
 /obj/structure/closet/crate/miningcar
 	name = "mine cart"
 	desc = "A cart for use on rails. Or off rails, if you're so inclined."