Measure OVS DPDK and OVS native VXLAN/GRE/GENEVE encapsulation performance.

Requirements/Changes:

• Create a new deployment scenario, Overlay_P2P.
• Setup DUT as TEP (Tunnel Endpoint) which performs encapsulation of frames and sends traffic to the 2nd traffic generator port.
• No decapsulation is performed in this testcase.
• Introduce a vsperf param, --run-integration, to filter tests to integration tests.