Start adding Miniflux support plus other cleanup

- Modernize old async code
- Update to .NET 10
- Adjust namespace
- Bypass update check when debugging

Application/Feeds/DataErrorDictionary.cs

@@ -3,7 +3,7 @@ using System.Collections;
 using System.Collections.Generic;
 using System.ComponentModel;
 
-namespace FeedCenter;
+namespace FeedCenter.Feeds;
 
 internal class DataErrorDictionary : Dictionary<string, List<string>>
 {