More elegant bindings generation

[sbihel]

I see two limitations with the way we generate language bindings:

• we write them manually and need to update them manually, when they're basically all the same (arguably, you can also say each has specific subtleties like the error handling in C bindings); and
• we constraint the benefits of type systems by only passing around strings.

A possibly useful project could be https://mozilla.github.io/uniffi-rs/, or write custom macros/attributes inspired by a project like Diesel.