Publish Systemd Services

[magula]

We should publish our systemd services in the repository, and provide an install script as part of prerequisites.py and / or setup.py.

[underscore-j]

imo this should be a third script (it is neither a prerequisite, nor should it be part of setup, as systemd is distro-specific [at least in theory]).
Further,, many users will not want to run the cms, and only need to prepare tasks and contests.