devel/jwt-cpp: A header only C++ library to JWT

A header only library for creating and validating JSON Web Tokens
in C++11.
The objective is to deliver a versatile and universally applicable
collection of algorithms, classes, and data structures, fostering
adaptability and seamless integration with other libraries.

This header library will be used as a build dependency of
www/domoticz and www/domoticz-devel starting 2025.1.

Approved by: 0mp (mentor)
Differential Revision: https://reviews.freebsd.org/D50569