feat(UserInfoFetcher): Add XFSC AAS backend

[fhennig]

Description

To integrade with gaia-x we need to fetch user claims from the AAS. this can be done with the UserInfoFetcher.

part of: https://github.com/stackabletech/marispace-x/issues/55

The integration test contains a small python container that mocks the API.

contains CRD changes, new backend: aas

        clusterConfig:
          userInfo:
            backend:
              aas:
                hostname: aas.$NAMESPACE.svc.cluster.local
                port: 5000

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: Add serviceaccounts to test containers
2. CRD changes approved
3. CRD documentation for all fields, following the style guide.
4. Helm chart can be installed and deployed operator works
5. Integration tests passed (for non trivial changes)
6. Changes need to be "offline" compatible

Reviewer

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1. Code contains useful comments
2. Code contains useful logging statements
3. (Integration-)Test cases added
4. Documentation added or updated. Follows the style guide.
5. Changelog updated
6. 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

[fhennig]

ci test: https://ci.stackable.tech/view/02%20Operator%20Tests%20(custom)/job/opa-operator-it-custom/86/ 🟢

[NickLarsenNZ]

Nice one. Left some comments, but pretty much non-blockers.

[nightkr]

Haven't reviewed the tests

[fhennig]

@nightkr @NickLarsenNZ I still need to fix the test and run it again, but I think code wise everything should be fine. i didn't want to click "Resolve" on the open things, I wanted to leave it to you.

Edit: new test run 🟢

[nightkr]

Still not a complete review

[nightkr]

Largely LGTM. Did not run the tests myself. Ticked docs since I agree with not documenting this while it's experimental.