Add Lunar Domain Exposure API as a source #45

It may be useful to add Lunar’s Domain Exposure API as an optional enrichment source for compromised domains.

The API returns domain-level exposure data related to infostealer logs and data breaches, including exposure counts, recent activity, malware families, affected services, and infected device metadata.

The API is free to use and does not require an API token.

Example:
https://api.lunarcyber.com/domain-exposure?domain=stryker.com