Helm SDK

[jeffmccune]

Refactor the Helm generator to use the Helm SDK.

Reasons:

1. Increase performance by avoiding a sub process.
2. Pin the helm version.
3. Reduce support issues with
4. Make the external dependency on helm optional, not required.
5. Private Helm Repositories #370

Need to decide if we replace the current Helm generator or add a new one. It may be nice to provide the flexibility to exec helm so users can choose their own helm version if they want, but this likely increases our support burden.

Related tasks

• Private Helm Repositories #370
• Pin Helm and Kustomize #339

[jeffmccune]

This blocks integration with Unity. Dan checked in and mentioned he'll follow up after the holidays.

It doesn't, we've switched unity to execute cue instead of holos