Add Rust bindings

[Rixxc]

This PR proposes a Rust binding for mlkem-native.

Some notes about the implementation:

• The bindings implement the KEM trait from the RustCrypto kem crate, which makes it a easy drop in replacement for the RustCrypto ml-kem crate
• Rust compiles the mlkem-native with avx2 support if the target architecture supports it
• acvp_mlkem.rs implements the acvp test binary using the Rust API, which allows the binding to be tested against the acvp test vectors
• The implementation performs a key check when deserializing the encapsulation and decapsulation keys. This is a bit redundant as the checks are also performed on every encap and decap operation by the mlkem-native library. I chose to do this as the trait definition of the kem crate do not allow for those operations to fail, which means the only option to handle those errors is to panic. But the keys are checked upon construction this case should never be triggered with a safe program.

Please let me know what you think about this approach.

[hanno-becker]

@Rixxc Can you comment on what all these packages are needed for?

[Rixxc]

There are only a few dependencies in that that are actually used at build- and runtime. The dependencies are:

Runtime Dependencies

• kem: which contains interface definition that the mlkem-native crate implements. This is the same interface that the ml-kem crate from RustCrypto uses. This allows for the mlkem-native crate to be used in generic code that expects objects that implement this interface and can be used as an easy drop-in replacement for the already existing and quit popular ml-kem crate.
• crypto-common: Is a dependency from kem
• hybrid-array: Is needed to implement the kem interface
• typenum: pulled in by hybrid-array
• rand_core: This crate contains interface definitions for RNGs, similar to the kem crate

Build Dependencies

• cc: Is needed to compile the C code of mlkem-native during build time of this crate
• find-msvc-tools: pulled in by cc, needed to compile the C code under Windows
• shlex: pulled in by cc, used to escape strings for a POSIX shell

Other Dependencies

The rest of the dependencies are just dev dependencies. They are pulled in due to the getrandom feature of of the kem create. They are only used in the examples in the mlkem-native create.

[hanno-becker]

Wrong year?

[Rixxc]

The edition field is used by the compiler. It specifies a set of features that the Rust compiler has to support to be able to compile the project.

[Rixxc]

I've updated the edition to the latest one

[Rixxc]

I've updated the edition to the latest one

[Rixxc]

I had to move the package definition to the root of the project as otherwise we most likely will encounter issues when trying to publish the crate

[Rixxc]

Shall I squash the commits before this PR gets merged? Also is the crate name of mlkem-native fine or should it rather be mlkem-native-rs?