Implement ChaCha20Poly1305 with CryptoKit on macOS

[vcsjones]

This implements ChaCha20Poly1305 on macOS using CryptoKit instead of OpenSSL. Since .NET 7 raised the minimum target to macOS 10.15, we don't need to worry about the Swift runtime availability and can link against the system runtime, which makes this more feasible where before it was not.

This currently does not add support for Apple platforms that are not macOS (i.e. iOS, tvOS) as there are additional linker challenges there that need to be solved.

ChaCha20Poly1305 on macOS is the "easy" one as CryptoKit and OpenSSL have 1:1 functionality. AES-GCM will be done as a follow up, as that work is more complicated and will need to continue to fall back to OpenSSL for some circumstances. But this intends to set the foundation for working with CryptoKit.

Contributes to #52482

/cc @filipnavara

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Issue Details

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This implements ChaCha20Poly1305 on macOS using CryptoKit instead of OpenSSL. Since .NET 7 raised the minimum target to macOS 10.15, we don't need to worry about the Swift runtime availability and can link against the system runtime, which makes this more feasible where before it was not.

This currently does not add support for Apple platforms that are not macOS (i.e. iOS, tvOS) as there are additional linker challenges there that need to be solved.

ChaCha20Poly1305 on macOS is the "easy" one as CryptoKit and OpenSSL have 1:1 functionality. AES-GCM will be done as a follow up, as that work is more complicated and will need to continue to fall back to OpenSSL for some circumstances.

This is currently blocked on #75160.

/cc @filipnavara

Author:	vcsjones
Assignees:	-
Labels:	area-System.Security
Milestone:	-

[filipnavara]

Thanks for reviving this!

[vcsjones]

It's green, so, I think this is ready for review.

[bartonjs]

@akoeplinger You got volunteered to me as someone who might have opinions on the cmake portion of this change.

[akoeplinger]

[akoeplinger]

CMake parts look good to me.