GravityGeneratorWindow to XAML UI (#4638)

* Move color handling to localization strings, small improvements

* Create/move files to UI namespace

* Actually change namespace

* Move to XAML

* Improve localization

Content.Client/Gravity/UI/GravityGeneratorBoundUserInterface.cs

@@ -0,0 +1,54 @@
+using Content.Shared.Gravity;
+using JetBrains.Annotations;
+using Robust.Client.GameObjects;
+using Robust.Shared.GameObjects;
+
+namespace Content.Client.Gravity.UI
+{
+    [UsedImplicitly]
+    public class GravityGeneratorBoundUserInterface : BoundUserInterface
+    {
+        private GravityGeneratorWindow? _window;
+
+        public bool IsOn;
+
+        public GravityGeneratorBoundUserInterface(ClientUserInterfaceComponent owner, object uiKey) : base (owner, uiKey)
+        {
+            SendMessage(new SharedGravityGeneratorComponent.GeneratorStatusRequestMessage());
+        }
+
+        protected override void Open()
+        {
+            base.Open();
+
+            IsOn = false;
+
+            _window = new GravityGeneratorWindow(this);
+
+            _window.Switch.OnPressed += _ =>
+            {
+                SendMessage(new SharedGravityGeneratorComponent.SwitchGeneratorMessage(!IsOn));
+                SendMessage(new SharedGravityGeneratorComponent.GeneratorStatusRequestMessage());
+            };
+
+            _window.OpenCentered();
+        }
+
+        protected override void UpdateState(BoundUserInterfaceState state)
+        {
+            base.UpdateState(state);
+
+            var castState = (SharedGravityGeneratorComponent.GeneratorState) state;
+            IsOn = castState.On;
+            _window?.UpdateButton();
+        }
+
+        protected override void Dispose(bool disposing)
+        {
+            base.Dispose(disposing);
+            if (!disposing) return;
+
+            _window?.Dispose();
+        }
+    }
+}