Pull domains stored in CyHy request documents

[mcdonnnj]

💡 Summary

We should pull in domains listed in federal entity request documents for scanning.

Motivation and context

We already add domains detected during CyHy scanning of federal IPs with the fed_hostnames.py script. With the addition of domain-based CyHy scanning in cisagov/cyhy-core#101 and cisagov/cyhy-commander#14, it would make sense to include any hostnames added for that purpose.

Implementation notes

It would be easiest to bolt this functionality onto the fed_hostnames.py script, but there may be some filtering that needs to be done to get it "right".

Acceptance criteria

• Hostnames found in a CyHy entity's request document are included for BOD scanning.