add support to scaffold oci helm registry charts

[acornett21]

Description of the change:

• Add support for OCI helm registries client to helm's download manager.
• Updating flag arguments for clarification
• Added an example for clarification

Motivation for the change:

• Fixes: release.sh: compare file versions against new version #610

Testing

• Example in the PR now works
• The follow where oci:// is passed is also supported operator-sdk create api --group demo --version v1alpha1 --kind Nginx --helm-chart oci://registry-1.docker.io/bitnamicharts/nginx:21.1.21

Checklist

If the pull request includes user-facing changes, extra documentation is required:

• Add a new changelog fragment in changelog/fragments (see changelog/fragments/00-template.yaml)
• Add or update relevant sections of the docs website in website/content/en/docs