UI - Added routing (#802)

ColorGradient - Fixed GetColor returning the first stop if position was after the last stop

src/Artemis.UI/Screens/SurfaceEditor/SurfaceEditorViewModel.cs

@@ -9,6 +9,7 @@ using Artemis.Core;
 using Artemis.Core.Services;
 using Artemis.UI.DryIoc.Factories;
 using Artemis.UI.Extensions;
+using Artemis.UI.Shared;
 using Artemis.UI.Shared.Services;
 using Avalonia;
 using ReactiveUI;
@@ -16,7 +17,7 @@ using SkiaSharp;
 
 namespace Artemis.UI.Screens.SurfaceEditor;
 
-public class SurfaceEditorViewModel : MainScreenViewModel
+public class SurfaceEditorViewModel : ActivatableViewModelBase, IMainScreenViewModel
 {
     private readonly IDeviceService _deviceService;
     private readonly IDeviceVmFactory _deviceVmFactory;
@@ -30,14 +31,13 @@ public class SurfaceEditorViewModel : MainScreenViewModel
     private double _overlayOpacity;
     private bool _saving;
 
-    public SurfaceEditorViewModel(IScreen hostScreen,
-        ICoreService coreService,
+    public SurfaceEditorViewModel(ICoreService coreService,
         IRgbService rgbService,
         ISurfaceVmFactory surfaceVmFactory,
         ISettingsService settingsService,
         IDeviceVmFactory deviceVmFactory,
         IWindowService windowService,
-        IDeviceService deviceService) : base(hostScreen, "surface-editor")
+        IDeviceService deviceService)
     {
         _rgbService = rgbService;
         _surfaceVmFactory = surfaceVmFactory;
@@ -71,6 +71,8 @@ public class SurfaceEditorViewModel : MainScreenViewModel
             }).DisposeWith(d);
         });
     }
+    
+    public ViewModelBase? TitleBarViewModel => null;
 
     public bool ColorDevices
     {