decal system & crayons (#5183)

Co-authored-by: Paul <ritter.paul1+git@googlemail.com>

Content.Shared/Decals/DecalGridComponent.cs

@@ -0,0 +1,23 @@
+using System.Collections.Generic;
+using Robust.Shared.Analyzers;
+using Robust.Shared.GameObjects;
+using Robust.Shared.Maths;
+using Robust.Shared.Serialization.Manager.Attributes;
+
+namespace Content.Shared.Decals
+{
+    [RegisterComponent]
+    [Friend(typeof(SharedDecalSystem))]
+    public class DecalGridComponent : Component
+    {
+        public override string Name => "DecalGrid";
+
+        [DataField("chunkCollection", serverOnly: true)]
+        public DecalGridChunkCollection ChunkCollection = new(new ());
+
+        public record DecalGridChunkCollection(Dictionary<Vector2i, Dictionary<uint, Decal>> ChunkCollection)
+        {
+            public uint NextUid;
+        }
+    }
+}