docs: Getting-started scripts - working helm script

[adwk67]

Description

Commented out ExternalIP from helm callout as the json parsing does not work on e.g. kind
Stackablectl works fine.

Definition of Done Checklist

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1. Changes are OpenShift compatible
2. Helm chart can be installed and deployed operator works

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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)

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

[sbernauer]

I don't really care, just wanted to mention that this now probably stops working on clouds such as GKE. Azure and IONOS.
Proper solution is something like kubectl get svc keycloak -o json | jq -r --argfile endpoints <(kubectl get endpoints keycloak -o json) --argfile nodes <(kubectl get nodes -o json) '($nodes.items[] | select(.metadata.name == $endpoints.subsets[].addresses[].nodeName) | .status.addresses | map(select(.type == "ExternalIP" or .type == "InternalIP")) | min_by(.type) | .address | tostring) + ":" + (.spec.ports[] | select(.name == "http") | .nodePort | tostring)'
Anyway, will be removed after listener-op integration in any case ;)