feat: support rechunking using Chunkah

[HastD]

Add a --chunkah option to bluebuild build that rechunks the image using Chunkah, a more modern, content-agnostic rechunker that's actively maintained and should offer various improvements over build-chunked-oci and the legacy rechunker.

This is implemented using a fairly generic "post-build hook" mechanism that allows a post-processing step (such as rechunking) to be applied after building the image but before tagging and pushing.

[gmpinder]

The cargo test job appears to be failing from some compilation error with OCI client

[gmpinder]

I'm seeing an error for the container chunkah build:

[21:25:50 TRACE blue_build_process_management::drivers::skopeo_driver:15] => SkopeoDriver::copy_oci(CopyOciOpts { src_ref: OciDir("/tmp/bluebuild-tmp-izCTpT3KHP/oci-out"), dest_ref: LocalStorage(Reference { registry: "localhost", mirror_registry: None, repository: "cli/test-chunkah", tag: Some("latest_linux_amd64"), digest: None }), privileged: false, retry_count: 0, podman_unshare: true })
[21:25:50 TRACE blue_build_process_management::drivers::skopeo_driver:29] => "podman" "unshare" "skopeo" "copy" "--all" "--" "oci:/tmp/bluebuild-tmp-izCTpT3KHP/oci-out" "containers-storage:localhost/cli/test-chunkah:latest_linux_amd64"
[21:25:50 containers-storage:localhost/cli/test-chunkah] => Error: please use unshare with rootless
[21:25:50 ERROR blue_build::commands:33] => Failed:
  × Failed to copy oci:/tmp/bluebuild-tmp-izCTpT3KHP/oci-out to containers-storage:localhost/cli/test-chunkah:latest_linux_amd64

[HastD]

@gmpinder I think it should be fixed now, but CI is failing due to network errors so I'm not 100% sure.

[gmpinder]

Just waiting on some builds to pass