[FEATURE]: Add cert-csi executables for all platforms in release

[atye]

The Makefile has a target to build cert-csi for Windows and Linux but the release only has the Linux build. Builds for all platforms can be added to the release, including darwin for Mac users.

Also, it would be better to have the binaries in the release asset directly instead of in a zip file.

[csmbot]

@atye: Thank you for submitting this issue!

The issue is currently awaiting triage. Please make sure you have given us as much context as possible.

If the maintainers determine this is a relevant issue, they will remove the needs-triage label and respond appropriately.

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