[CI/CD] Add automated test suite for PCF Provisioning API

[phine-lukas]

Context

With the introduction of the PCF Provisioning API, we require automated test coverage in the oai-cn5g-fed CI pipeline to validate endpoint health, schema validation, and policy behavior.

Proposed CI Work

• API Test Suite: Add a Python (requests/pytest) or Robot Framework script inside ci-scripts/ to execute CRUD operations (GET, POST, PUT, DELETE) against PCF provisioning HTTP REST endpoints.
• Policy Enforcement Verification: Verify that provisioned policy rules are correctly stored in the PCF and enforced upon session establishment.

Acceptance Criteria

• PCF Provisioning API endpoints are covered by automated CI tests.
• Pipeline fails cleanly if HTTP response status codes, schemas, or rule enforcement deviate from expectations.