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.
I am conflicted on this point. I like the idea of not having to specify a port (just like the driver and dialect) unless you are using something non-standard, but obviously the standard port varies for each database. My intention was to allow the puppet module to determine the port unless one was provided, if we default to postgres then any other database would always need to provide port even if standard for that database.

I could switch to creating a $candlepin::params::db_port and set it undef, but I know that doesn't really resolve your point.

We could also remove postgres as the default, but that breaks backwards compatibility.