DungeonData rework (#37172)

* DungeonData rework

Back to fields, serializes better, just make new layers dumby.

* wawawewa

* Fix this

* Fixes

* review

* thanks fork

* fix

Content.Shared/Procedural/PostGeneration/AutoCablingDunGen.cs

@@ -1,10 +1,12 @@
+using Robust.Shared.Prototypes;
+
 namespace Content.Shared.Procedural.PostGeneration;
 
 /// <summary>
 /// Runs cables throughout the dungeon.
 /// </summary>
-/// <remarks>
-/// DungeonData keys are:
-/// - Cabling
-/// </remarks>
-public sealed partial class AutoCablingDunGen : IDunGenLayer;
+public sealed partial class AutoCablingDunGen : IDunGenLayer
+{
+    [DataField(required: true)]
+    public EntProtoId Entity;
+}