decal system & crayons (#5183)

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

Content.Client/Decals/ToggleDecalCommand.cs

@@ -0,0 +1,15 @@
+using Robust.Shared.Console;
+using Robust.Shared.GameObjects;
+
+namespace Content.Client.Decals;
+
+public class ToggleDecalCommand : IConsoleCommand
+{
+    public string Command => "toggledecals";
+    public string Description => "Toggles decaloverlay";
+    public string Help => $"{Command}";
+    public void Execute(IConsoleShell shell, string argStr, string[] args)
+    {
+        EntitySystem.Get<DecalSystem>().ToggleOverlay();
+    }
+}