Pulp

We should do this:
http://alesnosek.com/blog/2016/12/04/controlling-a-multi-service-application-with-systemd/

To:
1. Provide a better user experience.
2. Ensure that if the order of starting the Pulp services ever becomes significant, they are stopped/started/restarted in the right order (currently, there seems to be no significance.)
3. Accomplish code cleanup in ansible-pulp.

This will work well for when ansible-pulp eventually supports api, content, workers, and resource-managers on separate hosts. Because the app can consist of multiple services, and each service's unit file declares that they are part of it. (i.e., we won't even have to template the app's .service file to accommodate the different set of services installed per host.)