Revert biome rework (#38724)

* Revert "Fix world generation (#38713)"

This reverts commit 10fa6ff4af.

* Revert "Biome rework (#37735)"

This reverts commit fe7b96147c.

Content.Shared/Procedural/PostGeneration/BiomeDunGen.cs

@@ -0,0 +1,21 @@
+using Content.Shared.Maps;
+using Content.Shared.Parallax.Biomes;
+using Robust.Shared.Prototypes;
+
+namespace Content.Shared.Procedural.PostGeneration;
+
+/// <summary>
+/// Generates a biome on top of valid tiles, then removes the biome when done.
+/// Only works if no existing biome is present.
+/// </summary>
+public sealed partial class BiomeDunGen : IDunGenLayer
+{
+    [DataField(required: true)]
+    public ProtoId<BiomeTemplatePrototype> BiomeTemplate;
+
+    /// <summary>
+    /// creates a biome only on the specified tiles
+    /// </summary>
+    [DataField]
+    public HashSet<ProtoId<ContentTileDefinition>>? TileMask;
+}