feat(GdPictureOptions): Created to configure parameters related to GdPicture.

- Configure the GdPicture license key via a third-party module entity.

EnvelopeGenerator.Finalizer/Models/GdPictureOptions.cs

@@ -0,0 +1,9 @@
+namespace EnvelopeGenerator.Finalizer.Models;
+
+public class GdPictureOptions
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    public string License { get; set; } = null!;
+}