<!-- * Use this issue template for suggesting new docs or updates to existing docs. Note: Doc work as part of feature development is covered in the Feature Request template. * For issues related to features of the docs.gitlab.com site, see https://gitlab.com/gitlab-org/gitlab-docs/issues/ * For information about documentation content and process, see https://docs.gitlab.com/ee/development/documentation/ --> ### Problem to solve PostgreSQL setup, configuration and maintenance documentation are spread across multiple pages, some of which are currently orphaned (e.g. pages under high availability). Let's consolidate everything into a single PostgreSQL topic section with sub-pages. ### Further details This MR serves as an illustration of what the final state might look like: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/29904. I'm closing that MR and breaking up the work into smaller chunks, represented by issues in this epic, so that it's more manageable.