Highlight default services and order of charms that will be upgraded

We should highlight which default services we attempt to upgrade and in which order from https://github.com/huntdatacenter/jujuna/blob/master/jujuna/settings.py so it is easier to understand what is going on and compare with the suggested order from https://docs.openstack.org/project-deploy-guide/charm-deployment-guide/latest/app-upgrade-openstack.html

Can we generate the list from the settings.py above in docs or something?