Build RPMs for Rocky and Alma (without reusing CentOS Stream RPMs)

[AkihiroSuda]

CentOS Stream 8 will reach its EOL within less than a year ahead of Rocky and Alma:

• CentOS Stream 8: 2024-05-31
• Rocky Linux 8: 2029-05-31
• AlmaLinux 8: 2029

So I suggest building RPMs for Rocky and Alma without reusing CentOS Stream RPMs.

An RPM binary for Rocky can be probably safely repurposed for Alma, and vice versa.

• [x] containerd RPMs: https://github.com/docker/containerd-packaging/pull/323
• [x] Docker RPMS: https://github.com/docker/packaging/pull/138
• [ ] install.sh (https://github.com/docker/docker-install)