add ability to export to APNG format

[scirocco-github]

PdfViewer appears to be a very safe way to view potentially suspicious or malicious PDF files, perhaps the safest.

Content Destruction / Reconstruction is one fairly certain method to ensure that no malicious content remains, and if PdfViewer could export a PDF file into a multi-page image format (APNG or gif?) then that resulting file would be rendered safe(r). Even better if PdfViewer could take that mulitpage image and create a simple, clean PDF

While this might be turning a viewer into a conversion utility of sorts, I think this functionality could be useful to a lot of people, particularly if it was very easy to use.

I'm no expert, and have come to this idea whilst searching for a way to reliably inspect/clean pdf files.

sources:
https://security.stackexchange.com/questions/260330/is-there-a-way-to-scan-a-pdf-to-ensure-it-doesnt-contain-anything-that-could-be
explains why pdf files have such a high potential for malicious content. Mentions CDR Content Destruction / Reconstruction

https://stackoverflow.com/questions/34551560/can-a-png-image-contain-multiple-pages
discusses multi-page PNG and other image formats. perhaps there's a better multi-page format?

https://blog.didierstevens.com/programs/pdf-tools/
old, but enlightening

https://github.com/tylabs/quicksand?tab=readme-ov-file#readme
the pdf scanning tool i was using to process pdfs for a risk score. the page has a broken link for the how to interpet the results archived copy