Dovesnap

- Update to debian bullseye
- Update pytype, prometheus, grafana, faucet, gauge, faucetconfrpc

- Upgrade docker, ruamel.yaml, prometheus

- Fix packaging.

- Driver name has changed from ovs to dovesnap
- Add cleanup_dovesnap script
- Update faucet, gauge, grafana, pytype, pylint, faucetconfrpc, ovs

- Make Join() and CreateEndpoint() non blocking again, but retain the head start on OFPort provisioning in CreateEn
dpoint.

- allocate OVS ports when endpoint is created, before container Join.
- allow preallocation of N FAUCET ports.
- trigger state reconcilation on webserver request for status
- upgrade pytype, prometheus, grpc