This begins the work to replace pg_* functions for database access
with the modern PDO interface.

We first migrate PostgreSQLTemplateDAO::GetById and GetByUserId
methods. We will progressively extend PDO usage to the rest of DAOs,
refactoring code as needed along the way.

Refactor common code in PostgreSQLTemplateDAO::GetById and GetByUserId
to the function runSelectQuery.

This leaves those functions looking similar to what they looked like
before, when they used the execute function from the non-PDO code
paths.

Rewrite method to use PDO prepared statements, typed binding and last
id retrieval.

The check that looked up the template in the database before removing
it was deleted because it was useless. The query will run, returning
zero affected rows, if the template doesn't exist. From the outside,
there is no change of behavior in the delete operation.

The missing PDO package in Debian is not a typo, it seems to be
provided by another package.

I'm removing the RHEL line because I don't have a RHEL system where
I can test things, and I don't want to provide unverified commands.

We need to modify the properties in the VO class to match column names.
Besides, the TemplateVO::setValues() function cannot be removed because
it's declared abstract in a parent class. This should be temporary,
until all DAOs use PDO.