[Perf] Add alternative transport mode for high speed long distance networks

[whoschek]

Add alternative transport mode for replicating over high speed long distance networks (High Bandwidth-Delay Product), for example AWS VPC peering between US, Europe and Asia. Must allow for TCP window size and buffer tuning and split a large individual transfer over multiple parallel streams. Must retain control flow over SSH but route data flow via a separate unencrypted non-ssh protocol, for example gridftp, bbcp, FDT, WDT. Retain same CLI usage, plus add relevant CLI config/tuning options.