Add Windows ARM64 (using ARM64X) support to CNG and PKCS#11

This will be useful for both openssl (using PKCS#11) and signtool (using CNG) on Windows ARM64. See the documentation at https://learn.microsoft.com/en-us/windows/arm/arm64x-pe#how-does-the-operating-system-use-arm64x-binaries .

It is possible to use the x64 versions of tools on Windows ARM64, but if you install an x64 DLL such as a CNG provider, any pure ARM64 program pointed to that CNG provider will encounter errors.

Windows ARM64 is becoming a more popular platform, so adding support earlier will ease developers’ lives as they transition to the new platform.

Start by locating the CNG and PKCS#11 integration entry points and reviewing the linked Windows ARM64X documentation. Determine the build, binary, and runtime requirements for supporting both pure ARM64 programs and existing x64 tooling; the work is done when both integrations operate on Windows ARM64.

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