Add ARM64 support for both dask and dask operator docker images

[VanWolf29]

Hello,

I've been trying to implement this in a Kubernetes cluster in AWS, but I prefer to use Graviton (ARM64) instances due to its benefits and optimal cost. However, I've noticed that there are not images supporting this architecture.

I could also volunteer for doing it (if possible) but I'd need a bit of orientation for the CI building the images.

Thanks!

[bstadlbauer]

@jacobtomlinson Please correct me if I'm wrong here, but images are built using chartpress (here) and chartpress should support ARM builds (jupyterhub/binderhub#1422) with using

chartpress \
    --builder docker-buildx \
    --platform linux/amd64 --platform linux/arm64 

The question would be more around whether we'd want to maintain another image. Happy to help testing here as I've got an ARM machine in case that's helpful.

[jacobtomlinson]

Yep no issues from me to add the other build.