Merge more UI refactor stuff (#11277)

* Changelog+options ui controller
* Sandbox UI controller
* Escape menu UI controller

Content.Client/UserInterface/Systems/EscapeMenu/ChangelogUIController.cs

@@ -0,0 +1,42 @@
+using Content.Client.Changelog;
+using JetBrains.Annotations;
+using Robust.Client.State;
+using Robust.Client.UserInterface.Controllers;
+
+namespace Content.Client.UserInterface.Systems.EscapeMenu;
+
+[UsedImplicitly]
+public sealed class ChangelogUIController : UIController
+{
+    private ChangelogWindow _changeLogWindow = default!;
+
+    public void OpenWindow()
+    {
+        EnsureWindow();
+
+        _changeLogWindow.OpenCentered();
+        _changeLogWindow.MoveToFront();
+    }
+
+    private void EnsureWindow()
+    {
+        if (_changeLogWindow is { Disposed: false })
+            return;
+
+        _changeLogWindow = UIManager.CreateWindow<ChangelogWindow>();
+    }
+
+    public void ToggleWindow()
+    {
+        EnsureWindow();
+
+        if (_changeLogWindow.IsOpen)
+        {
+            _changeLogWindow.Close();
+        }
+        else
+        {
+            OpenWindow();
+        }
+    }
+}