Use container-builder-shim 0.7.0, ensures use of Rosetta.

[jglogan]

• Addresses slow cross-platform builds from Very slow build time compared to Docker for Mac #68.

Type of Change

• Bug fix
• New feature
• Breaking change
• Documentation update

Motivation and Context

The shim wasn't doing everything needed to ensure the use of Rosetta for container build. The new shim adds an --enable-qemu option that controls whether `buildkit-qemu-emulator-x86_64 is available; when it is not available, buildkitd will attempt to build natively, meaning Rosetta will execute amd64 binaries.

Testing

• Tested locally
• Added/updated tests
• Added/updated docs

[jglogan]

Local tests

With container builder start --cpu 8 --memory 32g:

% container exec -it buildkit sh ps -ef
PID   USER     TIME  COMMAND
    1 root      0:08 /usr/local/bin/container-builder-shim --debug --vsock
   10 root      0:12 /usr/bin/buildkitd
   48 root      0:00 sh
  151 root      0:00 /usr/bin/buildkit-runc --log /var/lib/buildkit/runc-overlayfs/executor/runc-log.json --log-format json run --bundle /var/lib/buildkit/runc-overlayfs/executor/zedpr5mw5zq7nkcpqc0jqneo7 --keep zedpr5mw5zq7nkcpqc
  165 root      0:15 {dnf} /run/rosetta/rosetta /usr/bin/python3.9 /usr/bin/dnf module enable nodejs:22 -y
  182 root      0:00 ps -ef

With container builder start --cpu 8 --memory 32g --enable-qemu:

% container exec -it buildkit sh ps -ef
PID   USER     TIME  COMMAND
    1 root      0:07 /usr/local/bin/container-builder-shim --debug --vsock --platform linux/arm64,linux/amd64
   11 root      0:12 /usr/bin/buildkitd
   34 root      0:00 sh
  169 root      0:00 /usr/bin/buildkit-runc --log /var/lib/buildkit/runc-overlayfs/executor/runc-log.json --log-format json run --bundle /var/lib/buildkit/runc-overlayfs/executor/scpd0rp5ol1sdoiif8olzseim --keep scpd0rp5ol1sdoiif8
  183 root      0:02 {exe} .buildkit_qemu_emulator -0 dnf /usr/bin/dnf module enable nodejs:22 -y
  199 root      0:00 ps -ef