Rust wrappers for labrador ring

[yshekel]

This PR introduces Rust wrappers for rings in both direct and RNS representations, including support for vectorized operations (vec-ops) and NTT (Number Theoretic Transform).

Key Considerations

• To reuse existing APIs, FieldImpl and similar traits are implemented for rings. While this may seem unconventional, FieldImpl is not strictly tied to fields—it primarily provides utility methods such as one(), zero(), and from_hex().

• ICICLE rings “mock” fields by implementing inverse(), where non-invertible elements return 0. This approach ensures correct behavior where applicable (e.g., NTT, since twiddles have inverses).

• An alternative approach would be to introduce a separate API for rings, but this would lead to duplicated code and increased maintenance complexity.

• The RNS representation behaves similarly to extension fields, as it is another type in the crate with its own arithmetic and API.

• Rust wrappers for direct scalar

• Rust wrappers for RNS scalar

Next PRs:

• Rust wrappers for RNS<-->direct conversions
• New ring APIs (e.g. decomposition, matrix multiplication and more)
• Greyhound ring

[LeonHibnik]

🚀