Revert biome rework (#38724)

* Revert "Fix world generation (#38713)"

This reverts commit 10fa6ff4af.

* Revert "Biome rework (#37735)"

This reverts commit fe7b96147c.

Content.Shared/Parallax/Biomes/Layers/BiomeDecalLayer.cs

@@ -0,0 +1,34 @@
+using Content.Shared.Decals;
+using Content.Shared.Maps;
+using Robust.Shared.Noise;
+using Robust.Shared.Serialization;
+using Robust.Shared.Serialization.TypeSerializers.Implementations.Custom.Prototype.List;
+
+namespace Content.Shared.Parallax.Biomes.Layers;
+
+[Serializable, NetSerializable]
+public sealed partial class BiomeDecalLayer : IBiomeWorldLayer
+{
+    /// <inheritdoc/>
+    [DataField("allowedTiles", customTypeSerializer:typeof(PrototypeIdListSerializer<ContentTileDefinition>))]
+    public List<string> AllowedTiles { get; private set; } = new();
+
+    /// <summary>
+    /// Divide each tile up by this amount.
+    /// </summary>
+    [DataField("divisions")]
+    public float Divisions = 1f;
+
+    [DataField("noise")]
+    public FastNoiseLite Noise { get; private set; } = new(0);
+
+    /// <inheritdoc/>
+    [DataField("threshold")]
+    public float Threshold { get; private set; } = 0.8f;
+
+    /// <inheritdoc/>
+    [DataField("invert")] public bool Invert { get; private set; } = false;
+
+    [DataField("decals", required: true, customTypeSerializer:typeof(PrototypeIdListSerializer<DecalPrototype>))]
+    public List<string> Decals = new();
+}