Changes

card_key_provider: add PostgreSQL support

The Card Key Provider currently only has support for CSV files
as input. Unfortunately using CSV files does not scale very well
when the card inventory is very large and continously updated.
In this case a centralized storage in the form of a database
is the more suitable approach.

This patch adds a PostgreSQL support next to the existing CSV
file support. It also adds an importer tool to import existing
CSV files into the database.

Change-Id: Icba625c02a60d7e1f519b506a46bda5ded0537d3
Related: SYS#7725