Update Migrating from Terraform to Pulumi code samples

[jkodroff]

The code samples showing how to reference TF state on https://www.pulumi.com/docs/iac/adopting-pulumi/migrating-to-pulumi/from-terraform/#how-to-use-the-converter need to be updated:

• The examples still use an old version of the Terraform provider that no longer exists, and should be updated to demonstrate the Functions present in the new TF provider, rather than the RemoteStateReference resource..
• JavaScript examples should be removed (need to confirm)
• Java and YAML examples should be present
• The only supported backends with the current provider are local and remote. Additional backends can be added upon request. If a user wants this support they should comment on an issue in https://github.com/pulumi/pulumi-terraform/issues or add a new issue if the backend is not already in an existing issue.

[jkodroff]

@thoward Can you confirm that JavaScript examples should no longer be included in our pages? This seems to be the implicit style since the registry does not have JS, but it's not documented anywhere.

[jkodroff]

Answer from Troy: Ok to get rid of JS.