New Technical Articles guidelines

What does this MR do?

Create guidelines to new documentation guides and tutorials ("Technical Articles")

Why was this MR needed?

Establish minimum guidelines to be able to:

• Transfer blog posts currently in open MRs to documentation
• Proceed with indexes per topic
• Redact the community writers program (v2)

Todos

• Move pages guides under topics/pages/
• When https://gitlab.com/gitlab-com/www-gitlab-com/merge_requests/5361 gets merged => update link to "Writing Method"

License

• Add CC4 lincence (https://gitlab.com/gitlab-com/gitlab-docs/issues/95)
  • Add to gitlab-docs => https://gitlab.com/gitlab-com/gitlab-docs/merge_requests/68

Does this MR meet the acceptance criteria?

• Conform by the style guides
• Branch has no merge conflicts with master (if it does - rebase it please)

What are the relevant issue numbers?

closes https://gitlab.com/gitlab-com/gitlab-docs/issues/89 closes https://gitlab.com/gitlab-com/gitlab-docs/issues/87 closes https://gitlab.com/gitlab-org/gitlab-ce/issues/29525