Implement `noindex` meta tag in archived versions of the docs

Related to https://gitlab.com/gitlab-org/gitlab-docs/-/issues/913

We need to stop google from indexing old docs, so we should make sure the noindex tag is added to all archived docs: https://developers.google.com/search/docs/advanced/crawling/block-indexing

That way Google will stop serving up results for pages 12.10 versions of pages, for example.