Upstream Hostname into operator-rs

[nightkr]

Description

It's becoming useful in other operators, so let's try to share it.

As a bonus, by reusing the validation machinery in op-rs we can also add the validation rules to the CRD.

Op-rs equivalent: https://github.com/stackabletech/operator-rs/pull/851

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
- [x] Changes are OpenShift compatible
- [x] Helm chart can be installed and deployed operator works
- [x] Integration tests passed (for non trivial changes)
- [x] Changes need to be "offline" compatible

# Reviewer
- [ ] Code contains useful comments
- [ ] Code contains useful logging statements
- [ ] (Integration-)Test cases added
- [ ] Documentation added or updated. Follows the [style guide](https://docs.stackable.tech/home/nightly/contributor/docs/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](https://github.com/orgs/stackabletech/projects/25/views/1) has been updated

[nightkr]

Tests running: https://testing.stackable.tech/view/02%20Operator%20Tests%20(custom)/job/secret-operator-it-custom/7/, https://testing.stackable.tech/view/02%20Operator%20Tests%20(custom)/job/secret-operator-it-custom/8/

[nightkr]

The tests are green against kind, but red against OpenShift due to some SCC profile errors.. @razvan could this be related to #488?

[razvan]

The tests are green against kind, but red against OpenShift due to some SCC profile errors.. @razvan could this be related to #488?

No. It looks like you forgot to pass --test-suite openshift to the job parameters.

[nightkr]

Oh, that's not automatic? Gotcha.

[nightkr]

OpenShift round 2: https://testing.stackable.tech/view/02%20Operator%20Tests%20(custom)/job/secret-operator-it-custom/9/

[nightkr]

Openshift is green once running the correct suite.. :P

[sbernauer]

FYI, I put this issue on the board so that everyone has a chance to follow development :)