Add resource docs for terraform package

[lukehoban]

There are languages specific docs for the terraform provider, but not yet resource docs.

https://www.pulumi.com/docs/reference/pkg/nodejs/pulumi/terraform/

[AaronFriel]

Resolving #702 should fix this.

We should look at either porting the provider to the Go provider SDK, or hand-writing the schema.json.

[jkodroff]

Not clear to me what exactly the original issue is referring to, and considering its age, it might no longer be relevant, but there are resource docs for what I believe is the single resource in the SDK: state.RemoteStateReference:

https://www.pulumi.com/docs/reference/pkg/nodejs/pulumi/terraform/state/#RemoteStateReference

[iwahbe]

I think @lukehoban is referencing that https://www.pulumi.com/registry/ doesn't contain docs for this provider.