Merge more UI refactor stuff (#11277)

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

Content.Client/MainMenu/MainMenu.cs

@@ -2,6 +2,7 @@ using System.Text.RegularExpressions;
 using System.Threading.Tasks;
 using Content.Client.Options.UI;
 using Content.Client.MainMenu.UI;
+using Content.Client.UserInterface.Systems.EscapeMenu;
 using Robust.Client;
 using Robust.Client.ResourceManagement;
 using Robust.Client.UserInterface;
@@ -28,7 +29,6 @@ namespace Content.Client.MainMenu
         [Dependency] private readonly IUserInterfaceManager _userInterfaceManager = default!;
 
         private MainMenuControl _mainMenuControl = default!;
-        private OptionsMenu _optionsMenu = default!;
         private bool _isConnecting;
 
         // ReSharper disable once InconsistentNaming
@@ -46,8 +46,6 @@ namespace Content.Client.MainMenu
             _mainMenuControl.AddressBox.OnTextEntered += AddressBoxEntered;
 
             _client.RunLevelChanged += RunLevelChanged;
-
-            _optionsMenu = new OptionsMenu();
         }
 
         /// <inheritdoc />
@@ -57,7 +55,6 @@ namespace Content.Client.MainMenu
             _netManager.ConnectFailed -= _onConnectFailed;
 
             _mainMenuControl.Dispose();
-            _optionsMenu.Dispose();
         }
 
         private void QuitButtonPressed(BaseButton.ButtonEventArgs args)
@@ -67,7 +64,7 @@ namespace Content.Client.MainMenu
 
         private void OptionsButtonPressed(BaseButton.ButtonEventArgs args)
         {
-            _optionsMenu.OpenCentered();
+            IoCManager.Resolve<IUserInterfaceManager>().GetUIController<OptionsUIController>().ToggleWindow();
         }
 
         private void DirectConnectButtonPressed(BaseButton.ButtonEventArgs args)