Move logic from the HttpRequestIdEnricher into our own class so its not coupled to Serilog when attempting to get ReqId in UmbracoModule start & end log requests

src/Umbraco.Core/Logging/LogHttpRequest.cs

@@ -0,0 +1,32 @@
+using System;
+using System.Web;
+
+namespace Umbraco.Core.Logging
+{
+    public static class LogHttpRequest
+    {
+        static readonly string RequestIdItemName = typeof(LogHttpRequest).Name + "+RequestId";
+
+        /// <summary>
+        /// Retrieve the id assigned to the currently-executing HTTP request, if any.
+        /// </summary>
+        /// <param name="requestId">The request id.</param>
+        /// <returns><c>true</c> if there is a request in progress; <c>false</c> otherwise.</returns>
+        public static bool TryGetCurrentHttpRequestId(out Guid requestId)
+        {
+            if (HttpContext.Current == null)
+            {
+                requestId = default(Guid);
+                return false;
+            }
+
+            var requestIdItem = HttpContext.Current.Items[RequestIdItemName];
+            if (requestIdItem == null)
+                HttpContext.Current.Items[RequestIdItemName] = requestId = Guid.NewGuid();
+            else
+                requestId = (Guid)requestIdItem;
+
+            return true;
+        }
+    }
+}