* Remove old observability client
* Add initial functionality for prometheus querying
* Fix a copy-paste error in get_client()
* Add additional functionality.
This commit adds:
- commands:
delete
clear-tombstones
snapshot
- Better rbac injection as well as a possibility
to disable rbac.
- Configuration of prometheus_client through
env variables and /etc/openstack/prometheus.yaml
* Make README up to date
* Implement Martin's PR comments
* Implement better support for label values in rbac
* PEP8
