Merge branch 'sh-use-bundler' into 'master'

Use bundler to install Omnibus gems

See merge request https://gitlab.com/gitlab-org/omnibus-gitlab/-/merge_requests/7362

Merged-by: Balasankar 'Balu' C <[email protected]>
Approved-by: Balasankar 'Balu' C <[email protected]>
Reviewed-by: Balasankar 'Balu' C <[email protected]>
Reviewed-by: Robert Marshall <[email protected]>
Co-authored-by: Stan Hu <[email protected]>

Author: balasankarc