cleanup & refactor

Cleanup all the things. Major changes include:

*  <code>databases::postgresql</code> hates the way we install pg93, so hack around it
*  use yum_repository
*  use encrypted data bags
This will conflict with the "osl" repo we have in base. Since this repo is public, we really should create a public cookbook ``yum-osuosl`` and include that recipe here instead of putting it in this recipe.