Introduce Helm migration story

We know that there are many benefits from being able to convert Kubernetes YAML, and Helm Charts, to Pulumi, especially to leverage all the benefits of a language. However, it would also be possibly nice to be able to leverage the existing ecosystem of charts. For example:

import * as helm from "@pulumi/helm";
const datadog = new helm.Chart("datadog", {
    apiKey: ...,
    repository: ...,
});

These would clearly need to be weakly typed, although one could also imagine a world where we use code-gen to create even more first class resource types. Such as

import {Datadog} from "@pulumi/helm-charts";
const datadog = new Datadog({ /* yay, strong typing */ });

Assigning to @hausdorff to think about.

[joeduffy]

From my recent discussions with folks recently, not supporting a Tiller-based provider is actually a good thing anyway. It’s worth tracking how we’d dock in with the new CRD-based Helm system, however.

[hausdorff]

This can be marked as done. An ancillary note is that it turned out to be hard to write a Tiller provider, so we “just” wrote the Helm adopter.