Add ping controller and cleaning code

Controllers/Default/PingController.cs

@@ -0,0 +1,15 @@
+using Microsoft.AspNetCore.Mvc;
+
+namespace SkinsApi.Controllers.Default
+{
+    [Route("/ping")]
+    [ApiController]
+    public class PingController : ControllerBase
+    {
+        [HttpGet]
+        public async Task<IActionResult> Ping()
+        {
+            return Ok("Pong");
+        }
+    }
+}