trex: Add support Trex traffic generator

trex: Add support Trex traffic generator

Topology are two physical servers, on first is trex and second is VSPERF.
Trex is running in stateless mode this means that on server where is located
trex repo is running trex binary file and VSPERF working with server via
python API.

JIRA: VSPERF-528

Change-Id: Id8819495325ebc13fdce365f4af0e040ce68cd0e
Signed-off-by: Martin Goldammer <martin.goldammer6@gmail.com>
Reviewed-by: Martin Klozik <martinx.klozik@intel.com>
Reviewed-by: Al Morton <acmorton@att.com>
Reviewed-by: Christian Trautman <ctrautma@redhat.com>
Reviewed-by: Trevor Cooper <trevor.cooper@intel.com>