examples/flow_classify: add sample application

examples/flow_classify: add sample application

The flow_classify sample application exercises the following
librte_flow_classify API's:

rte_flow_classifier_create
rte_flow_classifier_query
rte_flow_classify_table_create
rte_flow_classify_table_entry_add
rte_flow_classify_table_entry_delete

It sets up the IPv4 ACL field definitions.
It creates table_acl and adds and deletes rules using the
librte_table API.

It uses a file of IPv4 five tuple rules for input.

Signed-off-by: Bernard Iremonger <bernard.iremonger@intel.com>
Acked-by: Jasvinder Singh <jasvinder.singh@intel.com>