Upgrade packages

Update namespaces
Clean up unused imports
Replace Avalonia.ReactiveUI with ReactiveUI.Avalonia 🙄

src/Artemis.UI/Screens/ProfileEditor/ProfileEditorViewModel.cs

@@ -4,6 +4,7 @@ using System.Collections.ObjectModel;
 using System.Linq;
 using System.Reactive;
 using System.Reactive.Disposables;
+using System.Reactive.Disposables.Fluent;
 using System.Threading;
 using System.Threading.Tasks;
 using Artemis.Core;