Merge branch 'yarn-docs-group-level-install' into 'master'

Add group level install in yarn docs

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/181612



Merged-by: Phillip Wells <pwells@gitlab.com>
Approved-by: Phillip Wells <pwells@gitlab.com>
Co-authored-by: Julian Paul Dasmarinas <jdasmarinas@gitlab.com>