Add missing psycopg2 dependency #111
Description
The following scenario fails :
We skip database installation via --skip-tags database, but we still want the databases & users to be created it raises an error saying that psycopg2 is missing (see error message)
This is because psycopg2 package is installed in the geerlingguy.postgresql role
We should ensure that psycopg2 is available prior using ansible modules that depends on it