Infrastructure for multicast/multi_subnet

client refers to a remote node with memory region.
server refers to this node. On dissemination node server issues the write/push/disseminate command. On delivery node server polls the cq for write-with-imm data and update KappaStreamInfo with new serial number.
Each client has its own pd, qp, cq and cq thread.
KappaStreamInfo keeps track of memory for a stream.
KappaDeliveryWorker::DeliverVideo calculates the circular buffer metadata on delivery based on last serial number.