add arm64 sftp image

[Ghostwritten]

I made a few changes:

docker pull --platform 'linux/arm64/v8' debian:bullseye
docker tag docker.io/library/debian:bullseye ghostwritten/debian:bullseye-arm64-v8

vim  /etc/buildkitd.toml
debug = true
[registry."docker.io"]
  mirrors = ["mirror.gcr.io"]


docker buildx create --use --bootstrap   --name mybuilder   --driver docker-container   --config /etc/buildkitd.toml
docker run --privileged --rm tonistiigi/binfmt --install all

vim Dockerfile
FROM infinilabs/debian:bullseye-arm64-v8

docker buildx build --platform linux/arm64  --push --tag infinilabs/sftp:v1.0-arm64 .

[Enrico204]

What is the improvement over #269 and #245 ?