Remove `hack/package-helm-charts.sh` or re-define its purpose and then re-implement

[jgehrcke]

It's the second release where this tool fails for me:

$ bash hack/package-helm-charts.sh 
Error: Invalid Semantic Version

It makes bad assumptions, and last time I noted for myself:

TODO: remove the hack/package-helm-charts.sh tooling or re-clarify its promise and then re-implement.

helm package works just fine, and is probably all we need:

$ helm package deployments/helm/nvidia-dra-driver-gpu
Successfully packaged chart and saved it to: <snikp>/nvidia-dra-driver-gpu-25.8.1.tgz