Generate Package API doc using cookiecutter API script

@yucongalicechen 

Could you please use the cookiecutter API workflow to generate a doc?

<img width="1089" alt="Screenshot 2024-10-04 at 10 38 42 AM" src="https://github.com/user-attachments/assets/5a26ee53-2d89-4789-9584-2717f913cc8c">

https://www.diffpy.org/diffpy.labpdfproc/api/diffpy.labpdfproc.html