Removed Storage.Close()'s return method since the pgx implementation of Close() doesn't return an error,
Removed Config.maxIdleConns since pgx implementation doesn't support setting a maximum number of idle connections
Right now, the default connection for postgres is `disable`. Some
databases require `verify` or even `required`.
This PR introduces a new implementation that allows the user to override
the `disable` mode. The PR keeps a backwards compatible config entry, that
sets the default behavior to `disable` if it's missing.