Use envtest framework in tests requiring a k8s apiserver

[randmonkey]

Problem Statement

Some reconcilers requires to build indices, so they cannot start without a real k8s APIserver. To effectively test them, we need to import envtest framework to provide a k8s server for running the reconciler.

Proposed Solution

Import envtest framework and add tests for the reconcilers requiring k8s APIserver in either:

• Unit tests
• Standalone "envtest" tests
  ...

Additional Information

...

Acceptance Criteria

• Reconcilers requiring a k8s APIserver can be effectively tested

[randmonkey]

dependent on #447.