[Meta] Initial pure Rust release

[franziskuskiefer]

A pure Rust libcrux release in 2024 with a limited set of primitives for use in different project.

Tracking of primitives backed by hacl-rs has been moved to #537.

[keks]

Is there anything in ML-DSA and ML-KEM itself that is not pure rust? My understanding is that we SHA3 and SHAKE are C right now, but other than that we are fine?

[franziskuskiefer]

ML-KEM and ML-DSA are pure Rust. We use the Rust SHA3.

[franziskuskiefer]

hmac could do with a verify function that tries to do constant time comparison of the two mac values.