The default systemd unit configuration for *certbot-renew.service* runs
the `certbot renew …` command as root. This can cause permissions
issues, since this Ansible role expects the *certbot* user to be able to
access all configuration, data, and log files. As such, this commit adds
a systemd unit extension for *certbot-renew.service* to run the command
as *certbot*.
The *certbot* role installs and configures the `certbot` ACME client. It
adjusts the default configuration to allow the tool to run as an
unprivileged user, and then configures Apache to work with the *webroot*
plugin. It registers for an account and requests a certificate for the
domains specified by the `certbot_domains` Ansible variable. Finally, it
enables the *certbot-renew.timer* systemd unit to schedule automatic
renewal of all Let's Encrypt certificates.
Dustin