Dev refine generator (#5426)

* add bernoulli module

* fix doc test

* add bernoulli functor

* make changes according to review

* refine (#5415)

* refine rng related tests; make generator.seed() as api

Co-authored-by: Ldpe2G <liangdepeng@gmail.com>
Co-authored-by: oneflow-ci-bot <69100618+oneflow-ci-bot@users.noreply.github.com>