* Add infrastructure roles configured globally.
Those are the roles defined in the operator itself. The operator's
configuration refers to the secret containing role names, passwords
and membership information. While they are referred to as roles, in
reality those are users.
In addition, improve the regex to filter out invalid users and
make sure user secret names are compatible with DNS name spec.
Add an example manifest for the infrastructure roles.
introduce Pod events channel;
add parsing of the MaintenanceWindows section;
skip deleting Etcd key on cluster delete;
use external etcd host;
watch for tpr/pods in the namespace of the operator pod only;