Added extensions for Field

Author: szv

src/Codebreaker.ViewModels/Models/Extensions/FieldExtensions.cs

@@ -0,0 +1,7 @@
+namespace Codebreaker.ViewModels.Models.Extensions;
+
+internal static class FieldExtensions
+{
+    public static IEnumerable<string> Serialize(this IEnumerable<Field> fields) =>
+        fields.Select(f => f.Serialize());
+}