The cryptography package has created all sorts of installation trouble over the last few years, probably because of mismatches between OS-installed packages and pip-installed packages. Using a virtualenv for all Python packages used by the management daemon should make sure everything is consistent.
See #1298, see #1264.
https://discourse.mailinabox.email/t/status-check-emails-empty-after-upgrading-to-v0-16/1082/3
A user on that thread suggests an alternate solution, adding `PYTHONIOENCODING=utf-8` to `/etc/environment`. Python docs say that affects stdin/out/err. But we also use these environment variables elsewhere to ensure that config files we read/write are opened with UTF8 too. Maybe all that can be simplified too.
* Created a new Python/flask-based management daemon.
* Moved the mail user management core code from tools/mail.py to the new daemon.
* tools/mail.py is a wrapper around the daemon and can be run as a non-root user.
* Adding a new initscript for the management daemon.
* Moving dns_update.sh to the management daemon, called via curl'ing the daemon's API.
This also now runs the DNS update after mail users and aliases are added/removed,
which sets up new domains' DNS as needed.
