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/PostGeneration/CorridorClutterPostGen.cs

@@ -0,0 +1,18 @@
+using Content.Shared.Storage;
+
+namespace Content.Shared.Procedural.PostGeneration;
+
+/// <summary>
+/// Adds entities randomly to the corridors.
+/// </summary>
+public sealed partial class CorridorClutterPostGen : IPostDunGen
+{
+    [DataField]
+    public float Chance = 0.05f;
+
+    /// <summary>
+    /// The default starting bulbs
+    /// </summary>
+    [DataField(required: true)]
+    public List<EntitySpawnEntry> Contents = new();
+}