Improve archives page
- Closes https://gitlab.com/gitlab-com/gitlab-docs/issues/254
- Related to: gitlab-com&20 (closed) // https://gitlab.com/gitlab-com/gitlab-docs/issues/238
- Explains the default version, links to where the docs are in each repo
- Renames "current" to "latest released"
- Starts with the default version, descending all the way through to the offline archives
@axil can you please review/merge? Tnx!
cc/ @mikelewis
Edited by Marcia Ramos