remove empty creds restriction (#10)

* removed empty checks on qbit and deluge credentials

* updated configuration readme

code/Infrastructure/Verticals/DownloadClient/QBittorrent/QBitService.cs

@@ -27,6 +27,11 @@ public sealed class QBitService : IDownloadService
 
     public async Task LoginAsync()
     {
+        if (string.IsNullOrEmpty(_config.Username) && string.IsNullOrEmpty(_config.Password))
+        {
+            return;
+        }
+        
         await _client.LoginAsync(_config.Username, _config.Password);
     }