Provide an image with different kubectl versions and Helm

[thardeck]

For our integration test we would also need an image with kubectl and helm installed, not just helm.
Maybe the charts image can provide different kubectl versions, which then can be targeted via creating a link as first step

You can add a helper script that each workflow calls in order to set the correct symlink for the versions that it needs.
That would also make sense for helm, because Helm v3 is at the moment is stored in the charts image as helm and Helm v4 as helmv4 which mean we would need to adapt our CI to use a different binary for for different versions.

[mallardduck]

Partially solved in: #31 - next steps are someone adding the kubectl versions to deps.yaml.