Adding ping testcase to demonstrate the isb Generic framework

Adding ping testcase to demonstrate the isb Generic framework

This patch defines
  - 2tg-topology-baremetal.yaml --> Define topology
  - pod.yaml -> sample pod.yaml describing TG & VNF unit details
  - tc.yaml --> test case in yardstick format (scenarios/context)
  - tg_ping_tpl.yaml --> VNF descriptor explaining how units are connected,
	eg Host (Xe0) --> Target (Xe0)
	   Host (Xe1) --> Target (Xe1)

JIRA: YARDSTICK-491
Change-Id:I41b69f457a6caa58d806cac9af8e831752ad314d
Signed-off-by: Deepak S <deepak.s@linux.intel.com>