Expose database cluster host atomically

[fermentfan]

Hi,
currently we're using the postgresql provider to setup our database clusters on Crunchy, but there is one thing that's bugging us. We need to have the atomic hostname of the connection string, to put it into the postgresql provider as it doesn't support connection strings.

Right now we rely on formatting strings with the cluster's ID in the hardcoded URL syntax.

[wilybrace]

@dennisvonderbey Thanks for the feedback. We've seen the need for exposing some of the connection string details atomically with other provider usage and will likely have additional fields available in the next release.