removed singleton inheritance and re implemented with thread safe

Main/src/main/java/Main.java

@@ -2,7 +2,7 @@ import Classes.SettingsManager;
 import Handlers.Web.Server;
 public class Main {
     public static void main(String [] args) {
-        SettingsManager Manager = new SettingsManager();
+        SettingsManager manager = SettingsManager.getInstance();
         Server.main(8888);
     }
 }