fix: remove required from entities' id

also adds "Global" entity for storing global configuration

Entities/Playlist.cs

@@ -1,7 +1,7 @@
 namespace Shadow.Entities;
 public class Playlist
 {
-	required public int Id { get; set; }
+	public int Id { get; set; }
 	required public string Name { get; set; }
 	required public string Uri { get; set; }
 	required public string Description { get; set; }