Write PodListeners

[nightkr]

Description

Part of #95, required by stackabletech/secret-operator#310. Requires stackabletech/operator-rs#644.

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
- [x] Helm chart can be installed and deployed operator works
- [x] Integration tests passed (for non trivial changes)

# Reviewer
- [x] Code contains useful comments
- [x] (Integration-)Test cases added
- [x] Changelog updated
- [x] 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

[nightkr]

This is largely R4R. There are currently no Antora docs, not sure about whether we want to surface this yet or treat it as an internal platform detail (@fhennig?).

[fhennig]

There are currently no Antora docs, not sure about whether we want to surface this yet or treat it as an internal platform detail

I think it's meant to be consumed and/or inform users, right? So it's a user facing feature. I'm also slightly worried that if we don't do it now, we will forget about documenting it in the future and/or have a harder time writing something about it.

[nightkr]

Primarily, it's intended to unblock stackabletech/secret-operator#310. It might be useful for debugging, but otherwise I'd consider it very niche.

[fhennig]

just two typos, LGTM otherwise

[siegfriedweber]

LGTM