The vast majority of our users will *not* use msmtp and might be
confused by this, especially in the tutorial. Bury it a little deeper
in the how-to section, which I'll add to in a minute.

This procedure was just tested live with status.torproject.org by
@lavamind.

Also, the daemon is configured to start automatically so there should be
no need to launch it manually.

Also adds a fix for schleuder-cli config

The default expiry was also changed in the GitLab admin web interface.

Closes: tpo/tpa/team#40561

This really helps figuring out team#40525.