flb_utils: add code to get the machine-id on windows machines.

[pwhelan]

Summary

Add support for windows machines to the flb_utils function flb_utils_get_machine_id using the MachineGuid registry key in HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Cryptography.

This is required for better fleet support since the default behavior in flb_utils_get_machine_id is to return a new UUID. This will lead to a new fleet configuration directory being created each time a fleet is invoked on a windows machine.

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Testing
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• Example configuration file for the change
• Debug log output from testing the change

• Attached Valgrind output that shows no leaks or memory corruption was found

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• Run local packaging test showing all targets (including any new ones) build.
• Set ok-package-test label to test for all targets (requires maintainer to do).

Documentation

• Documentation required for this feature

Backporting

• Backport to latest stable release.

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Fluent Bit is licensed under Apache 2.0, by submitting this pull request I understand that this code will be released under the terms of that license.

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