binary field: implement Bf1

[tcoratger]

Description

@Pratyush Here is my proposal to implement the first element of the binary tower, the basic binary field. The inspiration is taken from Binius repo: https://gitlab.com/IrreducibleOSS/binius

• For fields up to the fourth of the tower it is wise to use SmallU to benefit from the small size of the u8, then we can do something like what is proposed here https://gitlab.com/IrreducibleOSS/binius/-/blob/main/crates/field/src/binary_field.rs#L709

pub struct Bf1(U1);
pub struct Bf2(U2);
pub struct Bf4(U4);
pub struct Bf8(u8);
pub struct Bf16(u16);
pub struct Bf32(u32);
pub struct Bf64(u64);
pub struct Bf128(u128);

• I haven't made a macro yet because this is a first proposal with a single field. At first I think we can make several small basic PRs without a macro and see if at the end we can refactor with a macro but I don't think it's necessarily useful right away. Also for the Bf128, I think we can use the polyval base which seems a little more efficient (to test: https://github.com/RustCrypto/universal-hashes/tree/master/polyval) and so maybe it won't fit in the macro either, we'll see.

• @Pratyush Please provide feedback so that we can merge quite fast and iterate on that with small issues.

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