do not use Helm 3's crds/ folder that uses crd pre-install hook

As detailed in [1], CRDs that are applied through the CRD pre-install hook
will not ever be updated or upgraded. The Helm documentation reads [4]:

> The resources that a hook creates are not tracked or managed as part of
> the release. Once Tiller verifies that the hook has reached its ready
> state, it will leave the hook resource alone.
>
> Practically speaking, this means that if you create resources in a hook,
> you cannot rely upon helm delete to remove the resources. To destroy such
> resources, you need to either write code to perform this operation in a
> pre-delete or post-delete hook or add "helm.sh/hook-delete-policy"
> annotation to the hook template file.

On top of that, it seems to be not possible (after multiple trials) to
manage CRDs using Helm 3's crd-install hook using the crds/ folder [2]. It
seems like the only way would be to bundle crds inside the templates/ like
cert-manager has been doing for a while.

Note that installing CRDs using the templates/ way also causes trouble. Rob
Percival mentions in [1] that Helm has a problem with the CRD ordering [3]
and that the issue has not been fixed yet, which means installing operators
like google-cas-issuer breaks when the CRDs are inside templates/.

[1]: GoogleCloudPlatform/marketplace-k8s-app-tools#303
[2]: https://helm.sh/docs/developing_charts/#defining-a-crd-with-the-crd-install-hook
[3]: helm/helm#2994
[4]: https://v2.helm.sh/docs/developing_charts/#hook-resources-are-not-managed-with-corresponding-releases

Signed-off-by: Maël Valais <[email protected]>

Author: maelvls