Improving logging and request id (#189)

* hacking around to work out why logging and request id isnt working

* pass request id into logger so it can be structured, removed a bunch of debug logging we dont need because diagnostic trace gets it

* changed config dependency

* always have tracing available

* made it so we dont need to pass config into services.AddOcelot anymore with .net core 2.0

* add test

* lots of changes relating to logging and request ids, also updated documentation

* fixed failing test i missed

test/Ocelot.UnitTests/ServerHostedMiddlewareTest.cs

@@ -53,6 +53,12 @@
             ResponseMessage = Client.GetAsync(Url).Result;
         }
 
+        protected void WhenICallTheMiddlewareWithTheRequestIdKey(string requestIdKey, string value)
+        {
+            Client.DefaultRequestHeaders.Add(requestIdKey, value);
+            ResponseMessage = Client.GetAsync(Url).Result;
+        }
+
         public void Dispose()
         {
             Client.Dispose();