app/testpmd: add flow template management

app/testpmd: add flow template management

Add testpmd support for the rte_flow_pattern_template and
rte_flow_actions_template APIs. Provide the command line interface
for the template creation/destruction. Usage example:
  testpmd> flow pattern_template 0 create pattern_template_id 2
           template eth dst is 00:16:3e:31:15:c3 / end
  testpmd> flow actions_template 0 create actions_template_id 4
           template drop / end mask drop / end
  testpmd> flow actions_template 0 destroy actions_template 4
  testpmd> flow pattern_template 0 destroy pattern_template 2

Signed-off-by: Alexander Kozyrev <akozyrev@nvidia.com>
Acked-by: Ori Kam <orika@nvidia.com>