Generate systemd scripts

[tkuester]

This will be most useful for finishing off an install.

• Check the config for a redis backend, and look for the associated redis service
• Global vs local service scripts -- how to name?

We will leave it to the user to install the service files. At a later point, if we do debian packages, those can install the scripts for the user.

[tkuester]

Added proof of concept in 57c3829. Seems to work well so far.