Add support for Faults (#360)

* FaultType - wip

* .

* copy fault

* tests

* code-factor

* more tests

* fix tests

* fixed

* remove RANDOM_DATA_THEN_CLOSE

src/WireMock.Net/ResponseBuilders/Response.WithFault.cs

@@ -0,0 +1,14 @@
+namespace WireMock.ResponseBuilders
+{
+    public partial class Response
+    {
+        /// <inheritdoc cref="IFaultResponseBuilder.WithFault(FaultType, double?)"/>
+        public IResponseBuilder WithFault(FaultType faultType, double? percentage = null)
+        {
+            ResponseMessage.FaultType = faultType;
+            ResponseMessage.FaultPercentage = percentage;
+
+            return this;
+        }
+    }
+}