Setup busybox rootfs

[eureka-cpu]

Ref #34

Create the busybox filesystem for running lasr programs.

Pre-pulls the busybox image from dockerhub, streaming the image to stdout and loading it into the docker registry. This speeds up the node-start pre-script by having the image ready beforehand when building the container to create the rootfs.

[eureka-cpu]

So far this does the trick but not in the nix-way per se. It could be better but feel free to approve/merge once CI passes, and please check it out for yourself!

[andrewvious]

I've tested locally, the busybox rootfs dir is created and populated, however we are still getting the batcher error. Might require some fine tuning to get the payload dir working properly. Nice job! Nix 🤝 Docker

[eureka-cpu]

I've tested locally, the busybox rootfs dir is created and populated, however we are still getting the batcher error. Might require some fine tuning to get the payload dir working properly. Nice job! Nix 🤝 Docker

I know you've had some trouble with nix/docker interop in the past, but man. Nix really makes working with docker easy.