This commit provides a working implementation of a ruby
type/provider (`postgresql_psql` for handling the PSQL
commands. This is a little more flexible than doing it
via Exec resources, which is what the `postgresql::psql`
type was doing.
The old type is still present but now includes a
deprecation notification, and all of the other types
that were using the `::psql` type have been ported over
to use the `postgresql_psql` type instead.
One of the spec tests was creating a table to test
some user privileges. However, it wasn't dropping
the table afterwards, meaning that the same test
would fail on the next run because that table already
existed. This commit adds a command to drop the
table so that the tests can be run several times
in sequence.
