The certbot-auto client that I've been using for a long time is now
only supported if you install it using snap. I don't use snap on my
systems so I decided to switch to the acme.sh client, which is imp-
lemented in POSIX shell with no dependencies. One bonus of this is
that I can start using ECC certificates.
This also configures the .well-known directory so we can use webroot
when installing and renewing certificates. I have yet to understand
how the renewal works with regards to webroot, though. I may have to
update the systemd timers to point to /var/lib/letsencrypt/.well-known.
