Improve encryption key

[widhalmt]

We are now generating an encryiption key for sessions but we should provide the option to set one. Maybe improve on the way how it is calculated, too.

[lcndsmr]

Is this still up-to-date?

[widhalmt]

Unfortunately, yes. This refers to https://github.com/NETWAYS/ansible-collection-elasticstack/blob/main/roles/kibana/tasks/kibana-security.yml#L130 which is OK-ish but nothing more.

[Wintermute2k6]

Baby Step improvements https://github.com/NETWAYS/ansible-collection-elasticstack/tree/fix/improve_encryption_key