Adds 3 resources that will properly setup the RBAC:
1. service account, which is also assigned to the pods of the cluster, so that they use those particular permissions
2. a role, which holds only the necessary permissions that patroni members need to interact with k8s cluster
3. a rolebinding, which connects two two former things together to use.
The role and rolebinding was created using this tool https://github.com/liggitt/audit2rbac which looks at [audit logs](https://kubernetes.io/docs/tasks/debug-application-cluster/audit/#advanced-audit) provided by the api server.
* Use ConfigMaps or Endpoins for leader elections and to keep cluster state
* Label pods with a postgres role
* change behavior of pip install. From now on it will not install all dependencies, you have to specify explicitly DCS you want to use Patroni with: `pip install patroni[etcd,zookeeper,kubernetes]`
