feat: 싱글톤 제네릭 변경

MMOTestServer/MMOserver/Game/Channel/ChannelManager.cs

@@ -1,15 +1,10 @@
 using LiteNetLib;
+using MMOserver.Utils;
 
 namespace MMOserver.Game.Channel;
 
-public class ChannelManager
+public class ChannelManager : Singleton<ChannelManager>
 {
-    // 일단은 채널은 서버 켤때 고정으로간다 1개
-    public static ChannelManager Instance
-    {
-        get;
-    } = new ChannelManager();
-
     // 채널 관리
     private List<Channel> channels = new List<Channel>();