After migration of catalog to ERP5-ified document, its better to migrate all the catalog methods (`ZSQL Method, Python Script`) to new format. This will save the 
time during migration for developers and will reduce the chance for error during *import_in_old_format >> export_in_new_format* process.


Some important changes during re-export:
- Classes for new catalog methods are now defined via `portal_type`
- Filter is now defined via properties, so no need to save their properties in `.catalog_keys.xml` file.

/reviewed-on nexedi/erp5!518

erp5_pdm: use preferred category child item list method in my_variation_category_list field library.