Add Serverless Version of P&E's DNSMonitor Script

[arng4108]

🗣 Description

Adding the serverless version of P&E's existing DNSMonitor data collection script to XFD.

💭 Motivation and context

P&E is moving to a serverless architecture. As a result, the DNSMonitor data collection script that was originally developed to run on an EC2 instance needs to be updated so it can run in XFD's serverless architecture.

🧪 Testing

• Ran the script locally and confirmed it was running properly by viewing the logs and querying the local copy of the database it interacts with (verifying the correct records/data were inserted, etc.)
• Wrote unit tests for the script where possible, ran unit tests to ensure they pass
• Ran pre-commit on all files to check for linting/vulnerabilities/formatting

✅ Pre-approval checklist

• This PR has an informative and human-readable title.
• Changes are limited to a single goal - eschew scope creep!
• All future TODOs are captured in issues, which are referenced in code comments.
• All relevant type-of-change labels have been added.
• I have read the CONTRIBUTING document.
• These code changes follow cisagov code standards.
• All relevant repo and/or project documentation has been updated to reflect the changes in this PR.
• Tests have been added and/or modified to cover the changes in this PR.
• All new and existing tests pass.
• Bump major, minor, patch, pre-release, and/or build versions as appropriate via the bump_version script if this repository is versioned and the changes in this PR warrant a version bump.
• Create a pre-release (necessary if and only if the pre-release version was bumped).

✅ Pre-merge checklist

• Revert dependencies to default branches.
• Finalize version.

✅ Post-merge checklist

• Create a release (necessary if and only if the version was bumped).