Allow to have different versions of checks in scorecard.yaml for public and private repositories

[LeviPesin]

Some checks in scorecard.yaml like CII-Best-Practices, Contributors, and License can only work properly for public repositories (obvious for the first, for the second - it could be theoretically in private, but practically impossible, and the third can only score 9/10 for private repos), but others work well for both private and public repositories. It would be nice to have two different checks lists for private and public repositories.