[Reviewer: Rob] Add support for protocol independent (IPv4/IPv6) table indices based upon RFC 4001.

I believe this is a way to move forward from the IpAddress table indices used in the current MIB. I'm not sure it is the best way. It is more of an experiment, and a place to start the discussion of how to proceed.
The implementation did not match the current MIB’s OID definition for the sproutConnectedHomersTable and sproutConnectedHomesteadsTable (they were “reversed”).