Add migration for concurrent-download-chunk-size in container-runtime

[KCSesh]

Description of changes:

• Add migration for: concurrent-download-chunk-size which only works in containerd-2.1
  • containerd-2.1: add configurable concurrent-download-chunk-size setting bottlerocket-core-kit#645
  • feat: add concurrent_download_chunk_size to container-runtime bottlerocket-settings-sdk#99

Testing done:
Re-ran migration with released core-kit.

Tested migration: 1.46.0 -> 1.47.0 -> 1.46.0 on a custom eks-1.33 with containerd-2.1, and on aws-eks-1.32 (where the setting is a no-op)

1.46.0:

[ssm-user@control]$ apiclient set settings.container-runtime.concurrent-download-chunk-size="32mib"
Failed to change settings: Failed PATCH request to '/settings/keypair?tx=apiclient-set-sSym2oNqz9megGUk': Status 400 when PATCHing /settings/keypair?tx=apiclient-set-sSym2oNqz9megGUk: Unable to match your input to the data model.  We may not have enough type information.  Please try the —json input form.  Cause: Error during deserialization: unknown field concurrent-download-chunk-size, expected one of max-container-log-line-size, max-concurrent-downloads, enable-unprivileged-ports, enable-unprivileged-icmp, snapshotter at line 1 column 54

moved to 1.47.0:

[root@admin]#  apiclient set settings.container-runtime.concurrent-download-chunk-size="32mib"
[root@admin]# apiclient get settings.container-runtime.concurrent-download-chunk-size
{
  "settings": {
    "container-runtime": {
      "concurrent-download-chunk-size": 33554432
    }
  }
}

Back to 1.46.0:

[ssm-user@control]$ apiclient get settings.container-runtime.concurrent-download-chunk-size
{}
[ssm-user@control]$ apiclient get settings.container-runtime
{}

Terms of contribution:

By submitting this pull request, I agree that this contribution is dual-licensed under the terms of both the Apache License, version 2.0, and the MIT license.

[koooosh]

LGTM, aside from removing the maplit.workspace = true dependency