initial pass at making puppet-candlepin work for hosted environment

This is the initial round of changes needed to get hosted candlepin standing. There are more changes coming, primarily around additional configurability of candlepin.conf. I am certainly open to suggestions if there are any improvements you might suggest.
If postgres is the default database, to me it makes sense to put these values into params (thus they will get inherited by the main class) with the default postgres values. I think that may solve both issues.