Migrate content from Partners Page

In support of gitlab-com/www-gitlab-com!33931 (merged) and &2177 (closed), we need to migrate some content off of https://about.gitlab.com/partners/ and move it to a new home in https://docs.gitlab.com/

The content to be migrated should be:

• CLI Clients
• API Clients

We should move it to a new page at: https://docs.gitlab.com/developer/clients