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/IFaultRequestBuilder.cs

@@ -0,0 +1,18 @@
+using JetBrains.Annotations;
+
+namespace WireMock.ResponseBuilders
+{
+    /// <summary>
+    /// The FaultRequestBuilder interface.
+    /// </summary>
+    public interface IFaultResponseBuilder : ITransformResponseBuilder
+    {
+        /// <summary>
+        /// WithBody : Create a fault response.
+        /// </summary>
+        /// <param name="faultType">The FaultType.</param>
+        /// <param name="percentage">The percentage when this fault should occur. When null, it's always.</param>
+        /// <returns>A <see cref="IResponseBuilder"/>.</returns>
+        IResponseBuilder WithFault(FaultType faultType, [CanBeNull] double? percentage = null);
+    }
+}