New Extractor Idea: Internet Archive extractor

Extractor for Internet Archive content.

It should preserve the available item data and associated files across the different kinds of content hosted on archive.org, not just the rendered page.

This would make ArchiveBox treat Internet Archive URLs as archive collections with metadata and downloadable content, instead of only normal web pages.

Start by reading the existing extractor and plugin implementations in this repository, then review how Internet Archive URLs and archive.org item data are represented. Define the supported content types and verify that the finished extractor preserves each item's available metadata and associated downloadable files rather than only a rendered page.

Written by the indexing model from the issue text.