Use dialog instead of window for oopsies

Needlework.Net/Services/DialogService.cs

@@ -0,0 +1,20 @@
+using FluentAvalonia.UI.Controls;
+using System;
+using System.Threading.Tasks;
+
+namespace Needlework.Net.Services
+{
+    public class DialogService
+    {
+        public async Task<ContentDialogResult> ShowAsync<T>(object data)
+            where T : IDialog, IDisposable
+        {
+            T dialog = Activator.CreateInstance<T>();
+
+            var result = await dialog.ShowAsync(data);
+            dialog.Dispose();
+
+            return result;
+        }
+    }
+}