Externalize and share helm chart validation tooling

Summary

Some helm chart validation tools (tools/gci-templates/scripts/helm-schema-validation.sh, tools/gci-templates/scripts/helm-template-yamllint.sh) are duplicated between sylva-core and sylva-capi-cluster.

It may be useful to have only one instance of such tools, and shared them among helm chart projects

related references

related to this thread

Details

A dedicated project in sylva-elements hosting scripts and gitlab-ci template for using them.