This PR adds two different implementations of a way to verify members of the webring.
The first, verify.mjs simply makes sure that the listed URL only returns a response in the 2xx range. This is a quick spot check to make sure that the site owner doesn't redirect to a different location. The second, verifyDNS.mjs is slightly more complicated. It verifies, using DNS TXT records, whether a site owner controls their own domain by requiring a TXT record on the listed hostname. Both of these functions use Netlify's scheduled functions feature. verify runs daily and verifyDNS runs weekly. Obviously that timing can be changed by updating the value in netlify.toml.
Neither of these implementations solves the question as to what to do if one of these functions actually encounters that scenario. I don't know much about Netlify or whether it has logging or alerting functionality. Hopefully this helps in the discussion in #33 (closed).