[FEATURE] bindings/c: remove type abstraction to ensure thread safety

[extiop]

As described in https://github.com/ANSSI-FR/MLA/tree/master/bindings/C#caveat,
removing Box<dyn Trait> approach and using one with known types at compile time would ensure thread safety, thus the use of MLA Send feature. Though, it will require consequent code refactoring.