Replace kamaji-etcd with aenix-io/etcd-operator

[kvaps]

This change replaces kamaji-etcd with our own etcd-operator, which provides a robust environment for running etcd clusters.

The previous kamaji-etcd has not been removed yet, so it will continue to operate for compatibility purposes.

fixes: https://github.com/aenix-io/cozystack/issues/33

[kvaps]

@themoriarti, there are defaults provided by the etcd-operator maintainers. We can consider other values, but I think it might be better to address this in the upstream project.

https://github.com/aenix-io/etcd-operator/

[themoriarti]

We are waiting for a response from etcd-operator https://github.com/aenix-io/etcd-operator/issues/199 , if they make changes it will simplify the integration.

[themoriarti]

@kvaps Can you add the default value of requests and resource limits when creating an etсd cluster?