This commit added support to send rpc metrics to oslo.metrics.
Changes includes:
- Adding client wrapper for oslo.metrics to process metrics information
and send to oslo.metrics socket
- Modify rpc client to send metric when certain rpc events happens
For more information on oslo.metrics
https://opendev.org/openstack/oslo.metrics
Change-Id: Idf8cc0e52ced1f697ac4048655eff4c956fd5c79