feat(allowlist): exclude secret paths from review (#1262)

* feat(allowlist): exclude secret paths from review

* docs(review-rules): document secret exclusions

Built on the security finding by @wu21-web and the initial implementation in #1244 by @katepallewarprathmesh-sketch.

Co-authored-by: Prathmesh Katepallewar <284222233+katepallewarprathmesh-sketch@users.noreply.github.com>
Co-authored-by: Tao Xin <149216116+wu21-web@users.noreply.github.com>