Complete k8s integration tests

[pablochacin]

Description

Complete migration of kubernetes package tests to Testcontainers started with #323

Checklist:

• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works.
• I have run linter locally (make lint) and all checks pass.
• I have run tests locally (make test) and all tests pass.
• I have run relevant integration test locally (make integration-xxx for agent or kubernetes related changes)
• I have run relevant e2e test locally (make e2e-xxx for disruptors or cluster related changes)
• Any dependent changes have been merged and published in downstream modules
  

[roobre]

As I understand it, this removes the integration tests that were migrated to the new framework in #323, and additionaly migrates Test_UnsupportedKubernetesVersion. LGTM.