get_page_images(): only return images actually referenced by the given page

[andreasntr]

As per Document.get_page_images() docs:

this is not the list of images that are actually displayed.

This fix allows getting only the images actually referenced by the given page by comparing xrefs returned by Page.get_image_info(xrefs=True).

The list of images xrefs for each page is saved at Document creation time, filtering is performed only when invoking get_page_images on the document.

Request

I was able to write this code because i used this kind of workaround in a project of mine base on pymudf, however I'm not able to fully test it because the process of creating the test environment is not clear (pyproject.toml is empty for example). I'll be happy to test it when instructions are provided

[github-actions]

All contributors have signed the CLA ✍️ ✅
_{Posted by the CLA Assistant Lite bot.}

[andreasntr]

I have read the CLA Document and I hereby sign the CLA