Switch from openssl to rustls

[sbernauer]

We can do so, because rustls/rustls#184 was resolved
Tested using stackablectl and zookeeper-op and kind and IONOS

Description

Needed for stackabletech/stackable-cockpit#92

Definition of Done Checklist

• Not all of these items are applicable to all PRs, the author should update this template to only leave the boxes in that are relevant
• Please make sure all these things are done and tick the boxes

Author

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1. Changes are OpenShift compatible
2. CRD changes approved
3. Integration tests passed (for non trivial changes)

Reviewer

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1. Code contains useful comments
2. (Integration-)Test cases added
3. Documentation added or updated
4. Changelog updated
5. Cargo.toml only contains references to git tags (not specific commits or branches)

Acceptance

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1. Feature Tracker has been updated
2. Proper release label has been added