Add DPDK pktgen traffic generator

Add DPDK pktgen traffic generator

Add DPDK pktgen traffic generator. This traffic generator is designed
only to work in with a MQ aware runner. Implements two consumer methods:
  - runner_method_start_iteration
  - runner_method_stop_iteration

"run_traffic" method will only initialize the traffic profile object.
This traffic generator uses a socket port (LUA port, default 22022) to
send the command messages.

Link: http://pktgen-dpdk.readthedocs.io/en/latest/index.html
JIRA: YARDSTICK-1344

Change-Id: I89bba0f462fa1c22b33f1253f67f7c41e6e721a5
Signed-off-by: Rodolfo Alonso Hernandez <rodolfo.alonso.hernandez@intel.com>