[dpdk-dev] [RFC] app/testpmd: update to support shared Rx queue

To support shared Rx queue[1], plan to update testpmd with following
changes:
- Add ``--rxq-share`` to enable shared Rx queue if device supports.
- In verbose mode, dump mbuf->port for each received packet.
- Check forwarding configuration to make sure queue streams of same
  share group scheduled on same core.
- Change forwarding engines to locate source stream by each packet
  source port, update stream counters and forward according to source
  stream setup.

[1] https://mails.dpdk.org/archives/dev/2021-July/215575.html

Signed-off-by: Xueming Li <redacted>