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
It was kind of deep inside of the cookbook. I almost missed it too if I hadn't looked into it. My first clue was finding a yum-pgdg cookbook :) and then discovering it in the postgres cookbook.