Feature/secureli-435: Implement custom PII scan

[kathleen-hogan-slalom]

secureli-435

This PR implements a new, custom PII scan. This scan occurs separately from our existing scans which utilize pre-commit hooks external to the secureli codebase.

Changes

• Creates new PII Scanner and adds the scan to the existing Scan Action

Testing

• Unit tests updated
• Screenshot of manual test below:

Clean Code Checklist

• [x] Meets acceptance criteria for issue
• [x] New logic is covered with automated tests
• [x] Appropriate exception handling added
• [ ] Thoughtful logging included
• [x] Documentation is updated
• [ ] Follow-up work is documented in TODOs
• [ ] TODOs have a ticket associated with them
• [x] No commented-out code included