remove empty creds restriction (#10)

* removed empty checks on qbit and deluge credentials

* updated configuration readme

code/Common/Configuration/DelugeConfig.cs

@@ -23,10 +23,5 @@ public sealed record DelugeConfig : IConfig
         {
             throw new ArgumentNullException(nameof(Url));
         }
-
-        if (string.IsNullOrEmpty(Password))
-        {
-            throw new ArgumentNullException(nameof(Password));
-        }
     }
 }

code/Common/Configuration/QBitConfig.cs

@@ -25,15 +25,5 @@ public sealed class QBitConfig : IConfig
         {
             throw new ArgumentNullException(nameof(Url));
         }
-
-        if (string.IsNullOrEmpty(Username))
-        {
-            throw new ArgumentNullException(nameof(Username));
-        }
-
-        if (string.IsNullOrEmpty(Password))
-        {
-            throw new ArgumentNullException(nameof(Password));
-        }
     }
 }

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);
     }