Remove a single Certbot (LetsEncrypt) certificate from a server

I've been using Certbot to generate and renew Let's Encrypt certificates for most of my smaller sites and services, and recently I needed to move a site from one server to another. It was easy enough to build the new server, then generate the certificate on the new server and use it in Apache or Nginx's configuration.

However, on the old server I no longer wanted to have the old certificate get renewed every week/month/etc. during the certbot-auto cron runs, so I looked to see if there was a way to simply have Certbot delete a certificate. It turns out there's not, but there is an issue—adding -delete option to remove the cert files—to add this functionality.