Helm charts - use random passwords generated by operator

Currently we have passwords specified in the values file for each helm chart and the values are not very secure.

The idea is to comment that part out and leave it optional and just use default secret name and let operator generate the secrets.

If user specifies some custom secret name or if the default secret already exists operator should not overwrite it.

If passwords are specified in values file in that case they should be used and managed by helm.