app/testeventdev: introduce dpdk-test-eventdev app

app/testeventdev: introduce dpdk-test-eventdev app

The dpdk-test-eventdev tool is a Data Plane Development Kit (DPDK)
application that allows exercising various eventdev use cases. This
application has a generic framework to add new eventdev based test cases
to verify functionality and measure the performance parameters of DPDK
eventdev devices.

This patch adds the skeleton of the dpdk-test-eventdev application.

Signed-off-by: Jerin Jacob <jerin.jacob@caviumnetworks.com>
Acked-by: Harry van Haaren <harry.van.haaren@intel.com>