[meta] Docs: Introduce new GitLab self-hosted subscriptions and GitLab.com plans to the docs

For gitlab-com/www-gitlab-com#1906 (closed). Follows gitlab-com/www-gitlab-com#1907 (closed).

What

Introduce GitLab Libre, Starter, Premium, Ultimate, and GitLab.com Free, Bronze, Silver, and Gold to the documentation.

Description

For the new policy for the GitLab tiers, we need to update the "introduced in" and "available in" notes, and the product description in the GitLab docs landing page.

Proposal

Notes on the feature availability would follow this model:

• For GitLab CE features: Introduced in GitLab 9.5.
• For GitLab EE features: Introduced in GitLab Starter 9.1
• For GitLab.com: wait for the badges (gitlab-com/www-gitlab-com#1907 (closed))

I'm also updating https://about.gitlab.com/gitlab-ee/ to https://about.gitlab.com/products/, as the former doesn't have any information about Starter, Premium, and Ultimate.

Tasks:

• Update product description in https://docs.gitlab.com/ee/README.html#gitlab-documentation => https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/16862, https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/4365
• Update Enterprise tiers => https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/4365, https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/16867
  • "EES, EEP, EEU" => "Starter, Premium, Ultimate"
  • "Enterprise Edition Starter" => "Starter"
  • "Enterprise Edition Premium" => "Premium"
  • "Enterprise Edition Ultimate" => "Ultimate"
  • https://about.gitlab.com/gitlab-ee/ => https://about.gitlab.com/products/
• Update general terms (when applicable) => https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/17161 / https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/4576
  • Community Edition
  • Enterprise Edition
• Update docs: explain GitLab.com tiers => https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/17325, https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/4703
• Implement badges (from gitlab-com/www-gitlab-com#1907 (closed)) (for both self-hosted and GitLab.com subscriptions) => https://gitlab.com/gitlab-com/gitlab-docs/issues/173

cc/ @JobV @axil for feedback pls