Add `examples/` tests

[pmalek]

Problem statement

Currently this repo contains example manifests in examples/ dir. These manifests are not tested at any point.

This should change so that they are continuously tested in CI.

This issue tracks this.

Proposed solution

We could reuse KGO's approach in Makefile and from its CI.

Alternatively we could use a solution like https://github.com/kubernetes-sigs/kubectl-validate to just validate the examples against the CRD schemas

Acceptance criteria

• [ ] Examples from examples/ directory are tested in CI