Add configurability for RMR low latency and fast ACK

Add configurability for RMR low latency and fast ACK

Implement new configuration parameters 'lowLatency' and 'fastAck' into
xapp-frame to activate RMR's low latency (TCP NO_DELAY) feature and fast TCP
acknowledgements feature. By default, both of these features are disabled.
Note also that even if these features are activated in configuration, it
depends on the transport library underneath the RMR library whether the feature
is actually supported or not.

Signed-off-by: Timo Tietavainen <timo.tietavainen@nokia.com>
Change-Id: I720b325f6d3c23054c50b4a3548aed19d0725b5d