Made repository methods asynchronous. Simplified playlist repository. Use playlist manager in the app, and left playlist repository to only be used by the playlist manager.

Harmonia.Core/Data/JsonFileRepository.cs

@@ -14,13 +14,19 @@ public abstract class JsonFileRepository<TObject> : FileRepository<TObject> wher
 
     protected override string Extension => "json";
 
-    protected override TObject Deserialize(Stream stream)
+    protected override async Task<TObject> DeserializeAsync(Stream stream)
     {
-        return JsonSerializer.Deserialize<TObject>(stream) ?? new();
+        return await JsonSerializer.DeserializeAsync<TObject>(stream) ?? new();
     }
 
-    protected override string Serialize(TObject obj)
+    protected override async Task<string> SerializeAsync(TObject obj)
     {
-        return JsonSerializer.Serialize(obj, _options);
+        using MemoryStream memoryStream = new();
+        await JsonSerializer.SerializeAsync(memoryStream, obj, _options);
+
+        memoryStream.Position = 0;
+
+        using StreamReader reader = new(memoryStream);
+        return await reader.ReadToEndAsync();
     }
 }