app/testpmd: new commands for flex filter

app/testpmd: new commands for flex filter

Following commands of flex filter are removed:
  - add_flex_filter (port_id) len (len_value) bytes (bytes_string) mask (mask_value)
    priority (prio_value) queue (queue_id)
  - remove_flex_filter (port_id) index (idx)
  - get_flex_filter (port_id) index (idx)
New command is added for flex filter by using filter_ctrl API and new flex filter structure:
  - flex_filter (port_id) (add|del) len (len_value) bytes (bytes_value) mask (mask_value)
    priority (prio_value) queue (queue_id)

Signed-off-by: Jingjing Wu <jingjing.wu@intel.com>
Signed-off-by: Pablo de Lara <pablo.de.lara.guarch@intel.com>