Create a workspace and use traits instead of custom structs for derivations

Use trait instead of wrapper struct for features vec

Specialize features vecs

Add Deref impl to features Vec type

Add features vec struct

Convert field names to snake case

Make struct and fields public

Fix Features derive field ignore attribute

Downgrade proc-macro2

Add docs

Add ToOneHot proc macro

Upgrade proc macros libs

Make nb_features method const

Add method to get struct fields names

Add to_vec_without method