Build arm32 build_image containers on an aarch64 host

I need to request a new machine:

- New machine operating system (e.g. linux/windows/macos/solaris/aix):
- New machine architecture (e.g. x64/aarch32/arm32/ppc64/ppc64le/sparc):
- Provider (leave blank if it does not matter): Doesn't mattter, but it's a role for the Linux/aarch64 dockerhosts
- Desired usage: Building arm32 build containers which are currently built on sxa's native arm32 hosts
- Any unusual specification/setup required: Ability to build arm32 containers.
- How many of them are required: At least one.

Please explain what this machine is needed for: Removing reliance on sxa's hardware which currnetly has a tendancy ro tun out of space becuase some docker images are being left around on it. This is also consistent with the tried and tested approach we use for AQA containers where we build and use the image on aarch64 hosts (although, so far, we don't publish them to a remote repository on this platform). Needs to be able to produce something that is usable for builds and can be correctly built and published by the [centos7_docker_image_updater](https://ci.adoptium.net/job/centos7_docker_image_updater) (Dockerhub) and [build_image_updater](https://ci.adoptium.net/job/build_image_updater) (GHCR) jobs