New sample requests: Create an IAM service account and grant it a role

[shannonxtreme]

TL;DR

Add two new samples (or one sample with 2 region tags) for creating an IAM service account and then granting it a role on a resource. For example, creating a new service account for GKE nodes to use, then granting it the roles/container.defaultNodeServiceAccount role on the project.

Terraform Resources

1. Create a new IAM service account in a project (https://registry.terraform.io/providers/hashicorp/google/latest/docs/resources/google_service_account)
2. Grant a role on a resource (https://registry.terraform.io/providers/hashicorp/google/latest/docs/resources/google_service_account_iam#google_service_account_iam_binding)

Detailed design

For the sample, make the following values in variable syntax (all caps, underscore-delimited):

1. Role to grant: ROLE
2. Service account account_id value: SERVICE_ACCOUNT_ID
3. Service account display_name value: DISPLAY_NAME
4. Resource to grant the role on (in the terraform docs example I think it's "admin-account-iam"? ROLE_RESOURCE

For the IAM binding's member field, I think we can use serviceAccount:${google_service_account.sa.email}

Additional information

No response