feat: Adding DAG parsing profiler tool

[tiranux]

Description

Adding a new DAG tool to troubleshoot and profile DAGs parsing.

Note: Before submitting a pull request, please open an issue for discussion if you are not associated with Google.

Checklist

• [x] I have followed Sample Guidelines from AUTHORING_GUIDE.MD
• [x] README is updated to include all relevant information
• [ ] Tests pass: nox -s py-3.9 (see Test Environment Setup)
• [ ] Lint pass: nox -s lint (see Test Environment Setup)
• [x] Please merge this PR for me once it is approved