enh: Add Batch Pipeline

Add support for batch pipeline that creates a SageMaker Pipeline that contains 3 steps
1. Source - pulls source code.
2. Build - get's the latest approved model, and outputs CFN template for SM pipelines using `staging.json` and `prod.json` config files.
2. BatchStaging - creates a SageMaker pipeline for Staging.
3. BatchProd - creates a SageMaker pipeline for Production.

No files or tests are named. Start by inspecting the repository's existing SageMaker pipeline entry points and how staging.json and prod.json are consumed; then map the requested Source, Build, BatchStaging, and BatchProd stages. Done means the batch pipeline creates the stated staging and production pipelines and produces the required CloudFormation template.

Written by the indexing model from the issue text.