WebHook : UseFireAndForget + Delay (#803)

* UseFireAndForget

* ...

* delay

* async

* updated code accorsing to proposal

* Change nuget to package reference for WireMock.Net.Console.Net472.Classic, move the new FireAndForget into the main mapping, out of individual webhook mappings making it all or nothing, update tests, change Middleware to await or not the firing of all webhooks. Update models as needed. (#804)

Co-authored-by: Matt Philmon <Matt_Philmon@carmax.com>

* small update

* Tweak middleware and fix bug in example (#806)

Co-authored-by: Matt Philmon <Matt_Philmon@carmax.com>

* .ConfigureAwait(false)

Co-authored-by: mattisking <mattisking@gmail.com>
Co-authored-by: Matt Philmon <Matt_Philmon@carmax.com>

src/WireMock.Net.Abstractions/Admin/Mappings/MappingModel.cs

@@ -74,4 +74,9 @@ public class MappingModel
     /// The Webhooks.
     /// </summary>
     public WebhookModel[]? Webhooks { get; set; }
+
+    /// <summary>
+    /// Fire and forget for webhooks.
+    /// </summary>
+    public bool? UseWebhooksFireAndForget { get; set; }
 }