decal system & crayons (#5183)

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

Content.Server/Decals/Commands/RemoveDecalCommand.cs

@@ -0,0 +1,46 @@
+using Content.Server.Administration;
+using Content.Shared.Administration;
+using Robust.Shared.Console;
+using Robust.Shared.GameObjects;
+using Robust.Shared.IoC;
+using Robust.Shared.Map;
+
+namespace Content.Server.Decals.Commands
+{
+    [AdminCommand(AdminFlags.Mapping)]
+    public class RemoveDecalCommand : IConsoleCommand
+    {
+        public string Command => "rmdecal";
+        public string Description => "removes a decal";
+        public string Help => $"{Command} <uid> <gridId>";
+        public void Execute(IConsoleShell shell, string argStr, string[] args)
+        {
+            if (args.Length != 2)
+            {
+                shell.WriteError($"Unexpected number of arguments.\nExpected two: {Help}");
+                return;
+            }
+
+            if (!uint.TryParse(args[0], out var uid))
+            {
+                shell.WriteError($"Failed parsing uid.");
+                return;
+            }
+
+            if (!int.TryParse(args[1], out var rawGridId) ||
+                !IoCManager.Resolve<IMapManager>().GridExists(new GridId(rawGridId)))
+            {
+                shell.WriteError("Failed parsing gridId.");
+            }
+
+            var decalSystem = EntitySystem.Get<DecalSystem>();
+            if (decalSystem.RemoveDecal(new GridId(rawGridId), uid))
+            {
+                shell.WriteLine($"Successfully removed decal {uid}.");
+                return;
+            }
+
+            shell.WriteError($"Failed trying to remove decal {uid}.");
+        }
+    }
+}