Split database and user creation to separate files, and make them includable from other roles

[bwachter]

Currently the DB configuration needs to be manually done, while in some cases a role may already need what it needs. Would be good to split that out, and move some logic into roles. Would also need a cleanup run in the end, as we'd only know at the very end which users need to be deleted.

Problem: roles might run on other hosts, so need to figure out how to inject it to sql host