Add "Author" field to plugins.

Interfaces/IFilter.cs

@@ -47,6 +47,8 @@ namespace DiscImageChef.CommonTypes.Interfaces
         string Name { get; }
         /// <summary>Unique UUID of the plugin</summary>
         Guid Id { get; }
+        /// <summary>Plugin author</summary>
+        string Author { get; }
 
         /// <summary>
         ///     Closes all opened streams.