Add PigPDF

[castor-git]

Link to the service, library or dataset

https://pigpdf.com/

Category under which the entry should appear (select only one)

• Parsers, OCR and extraction
• Readers and viewers
• Creation and production
• Accessibility
• Datasets

Brief description of the entry

Browser-based PDF toolkit for organizing and converting files; supported local beta tools process files in the browser, and basic tools require no account.