Verify link health automatically and update table

[augusto-herrmann]

Build a script to automatically and periodically (with Github Actions) verify link health and update the table accordingly.

[jarofgreen]

Be warned that many sites may be behind things like Cloudflare and will be very good at blocking bots. You'll probably get a lot of false positives.

I'd suggest to start with just setting up something that made a report that a human can then check.