Add pg_hba.conf, and creation of user/db

In this change I add 3 states:

* Creation of a pg_hba.conf file.
  * At the moment I just covered Debian because I am not sure about the locations on RedHat & Arch.
  * It has a line in it for the desired database and user (line 3 of pg_hba.conf). You will have to scroll to the right to see that I chose md5 auth for that line. The spaces are so that values are populated in line with the column headers.
* Creation of an app db matching that line from the pg_hba.conf.
* Creation of an app user matching that line from the pg_hba.conf.

I also add the corresponding lines in the pillar example.

No need to accept this if it's too app-specific. Just thought you might be interested, or that it might help others browsing the issues. If it needs any cleanup, let me know.