Replace or remove PyPI download counts scraper

[ewan-escience]

To scrape PyPI download counts, we use https://api.pepy.tech/. However, that API now requires an API key for all requests to it, rendering our scraper unusable (and generating a lot of errors). We could either

• Pay for the API. However, the website has very little information about itself, so you have no idea who you're doing business with.
• Drop the scraper.
• Query the public Google Big Query dataset to get the download counts. However, only 1TB of queries is free each month, and a single query (i.e. for a single PyPI package) already uses several gigabytes of data, so we'd have to severely limit the amount we can scrape each month.

See also https://packaging.python.org/en/latest/guides/analyzing-pypi-package-downloads/

[jmaassen]

Would downloading the dataset be an option? If so we could analyze it ourselves. It would be good to do this on free infrastructure though, like DAS6 or so.