Build arXiv scraper

[Popolechien]

arXiv is a fairly popular repository for Physics papers, and it seems it can go into outages.

Options to build a scraper:

• scrape directly from their site
• Look into https://ar5iv.labs.arxiv.org/, which is a HTML renderer and would provide users with a much better user experience IMHO

[Popolechien]

Flagging https://github.com/karpathy/arxiv-sanity-preserver