[Core] Make errors recoverable ?

[Mathys-Gasnier]

Currently errors are "sent" to a callback to be handled by the user, but at the moment there is no way to recover from them...

Making the errors recoverable would allow fixing of some of them, like for the allocator sizes errors. I have no idea how error handling is currently implemented and if it's even feasible to make them recoverable, but it would make handling errors, especially in bindings for "safe" languages better.