Add a debug overlay for accessreaders (#9681)

> didnt pjb have issues with doing the control stuff in an overlay and just wanted direct texture draw

I ended up doing dis.

Content.Client/Access/Commands/ShowAccessReadersCommand.cs

@@ -0,0 +1,33 @@
+using Robust.Client.Graphics;
+using Robust.Client.ResourceManagement;
+using Robust.Shared.Console;
+
+namespace Content.Client.Access.Commands;
+
+public sealed class ShowAccessReadersCommand : IConsoleCommand
+{
+    public string Command => "showaccessreaders";
+    public string Description => "Shows all access readers in the viewport";
+    public string Help => $"{Command}";
+    public void Execute(IConsoleShell shell, string argStr, string[] args)
+    {
+        var collection = IoCManager.Instance;
+
+        if (collection == null) return;
+
+        var overlay = collection.Resolve<IOverlayManager>();
+
+        if (overlay.RemoveOverlay<AccessOverlay>())
+        {
+            shell.WriteLine($"Set access reader debug overlay to false");
+            return;
+        }
+
+        var entManager = collection.Resolve<IEntityManager>();
+        var cache = collection.Resolve<IResourceCache>();
+        var system = entManager.EntitySysManager.GetEntitySystem<EntityLookupSystem>();
+
+        overlay.AddOverlay(new AccessOverlay(entManager, cache, system));
+        shell.WriteLine($"Set access reader debug overlay to true");
+    }
+}