Move metric refer to ASP.NET repo

aspnetcore/log-mon/metrics/built-in.md

@@ -0,0 +1,15 @@
+---
+title: ASP.NET Core built-in metrics
+description: Built-in metrics for ASP.NET Core apps
+author: rick-anderson
+ms.author: riande
+ms.date: 10/18/2023
+ms.topic: reference
+uid: log-mon/metrics/built-in
+---
+
+# ASP.NET Core built-in metrics
+
+[!INCLUDE[](~/log-mon/metrics/built-in/includes/built-in10.md)]
+
+[!INCLUDE[](~/log-mon/metrics/built-in/includes/built-in8.md)]