Merge branch 'docs-i18n-create-japanese-directory' into 'main'

Create Japanese documentation directory

See merge request gitlab-org/gitlab-runner!5513



Merged-by: Joe Burnett <jburnett@gitlab.com>
Approved-by: Marcel Amirault <mamirault@gitlab.com>
Reviewed-by: Marcel Amirault <mamirault@gitlab.com>
Co-authored-by: rasamhossain <rhossain@gitlab.com>