Add new port www/py-flask-jwt-extended

Flask-JWT-Extended not only adds support for using JSON Web Tokens (JWT) to
Flask for protecting views, but also many helpful (and optional) features built
in to make working with JSON Web Tokens easier.

WWW: https://github.com/coleifer/flask-peewee

PR: 242819
Submitted by: Goran Mekić <meka@tilda.center>