feat(intake): port to v1betaapi

[yago-123]

Description

This PR migrates the current STACKIT Intake implementation to the new SDK hierarchy structure. In our case we must start using v1betaapi.

In order to perform this port we had to:

1. Update all SDK import paths of Intake to v1betaapi
2. Explicit use of DefaultAPI instead of using directly the client
3. Shift from pointers to values for required fields
4. Fix go-cmp to ensure unexported private fields do not affect the test output
5. Adjust some linting changes

Checklist

• Issue was linked above (not needed)
• Code format was applied: make fmt
• Examples were added / adjusted (see e.g. here) (not needed)
• Docs are up-to-date: make generate-docs (will be checked by CI)
• Unit tests got implemented or updated
• Unit tests are passing: make test (will be checked by CI)
• No linter issues: make lint (will be checked by CI)

[github-actions]

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