Add an ability to set multiple hosts per cluster about vulcanizer

[nickcanz]

Hi @Oloremo,

Your request does make sense, but at this time I'm wary of complicating the connection logic with retrying/round-robining requests.

For now, my expectation is that people using vulcanizer for a large cluster would point to some kind of load balancer and/or perhaps use some kind of existing service discovery to pass the host/port to vulcanizer.

Thank you for the request! But it's a little too complicated at this stage of the project.