Add French and Korean to Argo

What does this MR do?

This adds French and Korean languages to the repository's Argo configuration. This is in preparation for the French and Korean language translation process. This does not begin the translation process, it simply provides the necessary configuration so Argo can use it when the languages are ready to translation.

Why was this MR needed?

What's the best way to test this MR?

What are the relevant issue numbers?

• Related to https://gitlab.com/gitlab-com/localization/docs-site-localization/-/work_items/863