feat(module map): Enable Defines Module for library use

[Bruschidy54]

Hey there @antoinepalazzolo and @g-bourachot,

I'm currently helping develop a framework that uses your SDK. When "Define Module" is enabled, a module.modulemap file will automatically be generated, which is required to be able to use JSONWebToken in libraries in XCode 11.4+.

I would appreciate your review. Thanks!