ssh support

[XiaofengXie16]

This is a fantastic tool and it would be great if it can support ssh .

[jefftriplett]

I have started running into this more and more because of version mismatches from some of the various python:* Docker images vs. keeping up with modern Postgres.

So it would be nice if the pg_* commands could optionally be ran via SSH or I'm not sure what a better solution is outside of sadly not using a base python image :/