Document full psql access to database labs thin clone
This issue is about expanding documentation to cover:
- How to get/request access to postgres.ai database labs
- How to setup port-forwarding to access thin-clones using psql
https://about.gitlab.com/handbook/engineering/development/enablement/database/doc/gitlab-com-database.html#use-postgresai-currently-under-evaluation-to-work-with-a-thin-clone-of-the-database-includes-direct-psql-access-to-the-thin-clone might be a good place to put this.