Support Gemfile checksum in JiHu

related upstream MR Verify gem checksums against committed file

popped out from https://gitlab.com/gitlab-org/gitlab/-/merge_requests/118938#note_1374688877

Background

Upstream take bundler-checksum as tool to check of the integrity of gems, we also should create our own checksum file in JiHu.

Todos

• add JH checksum files
• merge Upstream checksum and JH checksum in code sync repo
• update the related JiHu validation docs !1754 (diffs)

Ref: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/119677