Add option to ProxySettings to append guid to mapping file (#838)

* Add option to ProxySettings to append guid to mapping file

* .

* .

* .

src/WireMock.Net/Settings/ProxyAndRecordSettings.cs

@@ -58,4 +58,9 @@ public class ProxyAndRecordSettings : HttpClientSettings
     /// Default value is false.
     /// </summary>
     public bool UseDefinedRequestMatchers { get; set; }
+
+    /// <summary>
+    /// Append an unique GUID to the filename from the saved mapping file.
+    /// </summary>
+    public bool AppendGuidToSavedMappingFile { get; set; }
 }

src/WireMock.Net/Settings/WireMockServerSettingsParser.cs

@@ -94,6 +94,7 @@ public static class WireMockServerSettingsParser
                 SaveMappingForStatusCodePattern = parser.GetStringValue("SaveMappingForStatusCodePattern", "*"),
                 SaveMappingToFile = parser.GetBoolValue("SaveMappingToFile"),
                 UseDefinedRequestMatchers = parser.GetBoolValue(nameof(ProxyAndRecordSettings.UseDefinedRequestMatchers)),
+                AppendGuidToSavedMappingFile = parser.GetBoolValue(nameof(ProxyAndRecordSettings.AppendGuidToSavedMappingFile)),
                 Url = proxyUrl!
             };