Map ListenerClass.spec.loadBalancerClass into Service.spec

[nightkr]

Description

Fixes #285, requires stackabletech/operator-rs#986

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

• Changes are OpenShift compatible
• CRD changes approved
• CRD documentation for all fields, following the style guide.
• Helm chart can be installed and deployed operator works
• Integration tests passed (for non trivial changes)
• Changes need to be "offline" compatible

Reviewer

• (Integration-)Test cases added
• Documentation added or updated. Follows the style guide.
• Changelog updated
• Cargo.toml only contains references to git tags (not specific commits or branches)

Acceptance

• Feature Tracker has been updated
• Proper release label has been added
• Roadmap has been updated

[nightkr]

OpenShift test succeeded: https://testing.stackable.tech/view/02%20Operator%20Tests%20(custom)/job/listener-operator-it-custom/9/console

K3s tests succeeded locally

[siegfriedweber]

LGTM