[265] Add file upload to allow mocking of file operations (#266)

* [265] Add file upload to allow mocking of file operations

* [265] Fix failing test

* Update code + add tests

* LocalFileSystemHandlerTests

* 1.0.13

* Fixed the file post to create the mapping folder if none exists to begin with, otherwise the file upload fails with 404 (can't find the folder to upload to).

* fix tests

* add more tests for LocalFileSystemHandler

* Added the head method for files to check if a file exists without returning it as a body.

* Add a test and fix the response message (head requires no body).

* Fix newline

* Fix newline.

* Fix the number of mapping tests

* Update tests and update client-interface-api

* Cleanup "MappingConverter.cs"

src/WireMock.Net/Client/IFluentMockServerAdmin.cs

@@ -167,5 +167,42 @@ namespace WireMock.Client
         /// </summary>
         [Post("__admin/scenarios")]
         Task<StatusModel> ResetScenariosAsync();
+
+        /// <summary>
+        /// Create a new File
+        /// </summary>
+        /// <param name="filename">The filename</param>
+        /// <param name="body">The body</param>
+        [Post("__admin/files/{filename}")]
+        Task<StatusModel> PostFileAsync([Path] string filename, [Body] string body);
+
+        /// <summary>
+        /// Update an existing File
+        /// </summary>
+        /// <param name="filename">The filename</param>
+        /// <param name="body">The body</param>
+        [Put("__admin/files/{filename}")]
+        Task<StatusModel> PutFileAsync([Path] string filename, [Body] string body);
+
+        /// <summary>
+        /// Get the content of an existing File
+        /// </summary>
+        /// <param name="filename">The filename</param>
+        [Get("__admin/files/{filename}")]
+        Task<string> GetFileAsync([Path] string filename);
+
+        /// <summary>
+        /// Delete an existing File
+        /// </summary>
+        /// <param name="filename">The filename</param>
+        [Delete("__admin/files/{filename}")]
+        Task<StatusModel> DeleteFileAsync([Path] string filename);
+
+        /// <summary>
+        /// Check if a file exists
+        /// </summary>
+        /// <param name="filename">The filename</param>
+        [Head("__admin/files/{filename}")]
+        Task FileExistsAsync([Path] string filename);
     }
 }