Build and publish packages for AlmaLinux 10

AlmaLinux 10 released in May: https://almalinux.org/blog/2025-05-27-welcoming-almalinux-10/

We should build and publish packages for it.

Tracking this MR: !8523 (merged)

Acceptance Criteria

• Confirm PackageCloud supports Alma/EL 10: https://packagecloud.io/docs#anchor-el
• Add a Alma 10 builder to https://gitlab.com/gitlab-org/gitlab-omnibus-builder -> Previous Example gitlab-omnibus-builder!273 (merged)
• Update Omnibus CI to build and publish Alma 10 packages
• Update our supported platforms: https://docs.gitlab.com/install/package/#supported-platforms