feat: add experience info helper

Client/Domain/Helpers/ExperienceHelperInterface.cs

@@ -0,0 +1,13 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Client.Domain.Helpers
+{
+    public interface ExperienceHelperInterface
+    {
+        ulong GetExperienceToLevel(uint level);
+    }
+}