Add published helm chart

[mborne]

• charts/crash-test : the helm chart
• mborne/crash-test : github action to publish chart to OCI
• tests/version-sync.test.js : ensure version consistency between package.json / manifests (kustomize) and helm chart
• mborne/docker-devbox - argocd/apps/crash-test.yaml : deploy with ArgoCD (declarative)
• cleanup (useless version retrieval in github action) / document usage