Haunted dungeon template (#23768)

* haunted dungeon

* Initial work

Still needs prefab gen work to make it interesting.

* ime a worm

* weh

* Work

* Slight tweaks

---------

Co-authored-by: metalgearsloth <comedian_vs_clown@hotmail.com>

Content.Shared/Procedural/Dungeon.cs

@@ -15,6 +15,8 @@ public sealed class Dungeon
 
     public readonly HashSet<Vector2i> CorridorExteriorTiles = new();
 
+    public readonly HashSet<Vector2i> Entrances = new();
+
     public Dungeon()
     {
         Rooms = new List<DungeonRoom>();
@@ -23,5 +25,10 @@ public sealed class Dungeon
     public Dungeon(List<DungeonRoom> rooms)
     {
         Rooms = rooms;
+
+        foreach (var room in Rooms)
+        {
+            Entrances.UnionWith(room.Entrances);
+        }
     }
 }