calyptia: generate machine id for fleet agents

[patrick-stephens]

/etc/machine-id is not guaranteed to be unique so instead we generate a UUID locally to use in the fleet config directory. On first boot this will be created but after that should be reloaded.

macOS builds are still blocked by cprofiles issue, unrelated to this change.

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[patrick-stephens]

Unrelated unit test failures tracked here: #9682