feat: add Iowa liquor sales samples for Vertex AI Forecasting tutorial

[ghost]

Description

Adding samples of the Iowa liquor sales dataset to create a BQ Vertex AI Forecasting tutorial.

Checklist

• Please merge this PR for me once it is approved.
• If this PR adds or edits a dataset or pipeline, it was reviewed and approved by the Google Cloud Public Datasets team beforehand.
• If this PR adds or edits a dataset or pipeline, I put all my code inside datasets/<YOUR-DATASET> and nothing outside of that directory.
• If this PR adds or edits a dataset or pipeline that I'm responsible for maintaining, my GitHub username is in the CONTRIBUTORS file.
• This PR is appropriately labeled.

[adlersantos]

Just a few simple changes and we're good to go.

Please regenerate the Terraform and DAG files after the YAML revisions. Thanks!