Draft: Refactor sylva-units helm charts OCI workflow

What does this MR do and why?

💡 This MR would be more easy to review one commit at a time.

Makes use of

apiVersion: source.toolkit.fluxcd.io/v1beta2
kind: OCIRepository
metadata:
  name: podinfo
spec:
  url: oci://ghcr.io/stefanprodan/charts/podinfo
  ref:
    tag: "6.5.0"
---
apiVersion: helm.toolkit.fluxcd.io/v2
kind: HelmRelease
metadata:
  name: podinfo-internal
spec:
  chartRef:
    kind: OCIRepository
    name: podinfo-chart
    namespace: podinfo

instead of

apiVersion: source.toolkit.fluxcd.io/v1
kind: HelmRepository
metadata:
  name: podinfo
spec:
  type: oci
  url: oci://ghcr.io/stefanprodan/charts/podinfo
---
apiVersion: helm.toolkit.fluxcd.io/v2
kind: HelmRelease
metadata:
  name: podinfo
spec:
  interval: 10m
  timeout: 5m
  chart:
    spec:
      chart: podinfo
      version: "6.5.0"
      sourceRef:
        kind: HelmRepository
        name: podinfo

from proposal https://github.com/fluxcd/helm-controller/issues/789. Considerations of this feature are defined in https://github.com/fluxcd/helm-controller/blob/main/docs/spec/v2beta2/helmreleases.md#chart-reference.

A drawback with this approach is we can no longer use HelmRelease.spec.chart.spec.valuesFiles, while a feature request suggestion to move to HelmRelease.spec.valuesFiles was already done by @tmmorin in https://github.com/fluxcd/helm-controller/issues/814#issuecomment-1878895581.

Related reference(s)

Concerns a sylva-units evolution proposed by #1738

Verify the Integrity and Authenticity of OCI Artifacts #451 (closed)

Test coverage

CI configuration

Below you can choose test deployment variants to run in this MR's CI.

Click to open to CI configuration

Legend:

Icon	Meaning	Available values
☁️	Infra Provider	capd, capo, capm3
🚀	Bootstrap Provider	kubeadm (alias kadm), rke2
🐧	Node OS	ubuntu, suse
🛠️	Deployment Options	light-deploy, oci, ha, misc
🎬	Pipeline Scenarios	no-wkld simple-update simple-update-no-wkld rolling-update rolling-update-no-wkld wkld-k8s-upgrade nightly sylva-upgrade sylva-upgrade-no-wkld sylva-upgrade-from-x.x.x preview

• 🎬 preview ☁️ capd 🚀 kadm 🐧 ubuntu

• 🎬 preview ☁️ capo 🚀 rke2 🐧 suse

• 🎬 preview ☁️ capm3 🚀 rke2 🐧 ubuntu

• ☁️ capd 🚀 kadm 🛠️ dev-sources,light-deploy 🐧 ubuntu

• ☁️ capd 🚀 rke2 🛠️ light-deploy 🐧 suse

• ☁️ capo 🚀 rke2 🐧 suse

• ☁️ capo 🚀 kadm 🐧 ubuntu

• ☁️ capo 🚀 rke2 🎬 rolling-update 🛠️ ha 🐧 ubuntu

• ☁️ capo 🚀 kadm 🎬 rolling-update 🛠️ ha 🐧 ubuntu

• ☁️ capo 🚀 kadm 🎬 wkld-k8s-upgrade 🐧 ubuntu

• ☁️ capo 🚀 rke2 🎬 rolling-update-no-wkld 🛠️ ha,misc 🐧 suse

• ☁️ capo 🚀 rke2 🎬 sylva-upgrade-from-1.3.x 🛠️ ha,misc 🐧 ubuntu

• ☁️ capm3 🚀 rke2 🐧 suse

• ☁️ capm3 🚀 kadm 🐧 ubuntu

• ☁️ capm3 🚀 kadm 🎬 rolling-update-no-wkld 🛠️ ha,misc 🐧 ubuntu

• ☁️ capm3 🚀 rke2 🎬 wkld-k8s-upgrade 🛠️ ha 🐧 suse

• ☁️ capm3 🚀 kadm 🎬 rolling-update 🛠️ ha 🐧 ubuntu

• ☁️ capm3 🚀 rke2 🎬 sylva-upgrade-from-1.3.x 🛠️ misc,ha 🐧 suse

• ☁️ capm3 🚀 kadm 🎬 rolling-update 🛠️ ha 🐧 suse

Global config for deployment pipelines

• autorun pipelines
• allow failure on pipelines

Notes:

• Enabling autorun will make deployment pipelines to be run automatically without human interaction
• Disabling allow failure will make deployment pipelines mandatory for pipeline success.
• if both autorun and allow failure are disabled, deployment pipelines will need manual triggering but will be blocking the pipeline

Be aware: after configuration change, pipeline is not triggered automatically. Please run it manually (by clicking the run pipeline button in Pipelines tab) or push new code.