Feature Idea: Support scanning public github events for a set of users

[CameronLonsdale]

Some code I've written which might be useful for other kingfisher users is the following:

1. Submit a list of github usernames
2. For each user: Fetch github events for that user from the past X hours
3. If event == PushEvent, scan all commits in event
4. If event == branchEvent, scan entire branch
5. If event == CreateEvent, scan entire repo.

This is pretty similar to what monitoring solutions like GitGuardian do, and is useful for defenders who want to monitor employees public commits for secrets.

Up to you whether you think it's something worth including in kingfisher or not!