Provide systemd unit files for all calamari daemons

This is a proposal to include [systemd unit files](https://www.freedesktop.org/software/systemd/man/systemd.service.html) for calamari daemons. Right now, calamari services are managed by [supervisord](http://supervisord.org/) instead.
# Reasoning

Since both [Fedora](https://fedoraproject.org/wiki/Systemd) and [Debian](https://wiki.debian.org/systemd) distributions (and their derivates, such as RHEL or Ubuntu) are using systemd now, it would make sense to add systemd unit files for calamari so that on such linux distributions, superviord configuration could be replaced with systemd one. This would mean simplification of service management and better integration with the rest of the daemons.