Allow using Helm charts as bases and values.yaml file patching in overlays

[pentago]

Eschewed features

• [X] This issue is not requesting templating, unstuctured edits, build-time side-effects from args or env vars, or any other eschewed feature.

What would you like to have added?

I'd like to have ability to use Helm charts as regular base and allow patching of that base with different values.yaml as patches in overlays, like this:

.
├── base
│   ├── Chart.yaml
│   ├── kustomization.yaml
│   └── values.yaml
└── environments
    ├── dev
    │   ├── kustomization.yaml
    │   └── prod-values.yaml
    ├── prod
    │   ├── kustomization.yaml
    │   └── prod-values.yaml
    └── stage
        ├── kustomization.yaml
        └── stage-values.yaml

Why is this needed?

Something like this would make Helm charts first-class citizens in Kustomize projects and allow for uniform patching to standard Kubernetes YAML manifests.

Can you accomplish the motivating task without this feature, and if so, how?

Only by using a lot of duplication like using full values.yaml for each overlay.

What other solutions have you considered?

Not aware of anything else doing this and would love to get this thing done with only Kustomize.

Anything else we should know?

No response

Feature ownership

• [ ] I am interested in contributing this feature myself! 🎉

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