swagger integration

[Leonardo Mauro]

Automatize the Swagger documentation to generate a simple documentation based on the flask.
Additional documentation:

• https://pypi.org/project/flask-swagger/
• https://flask-restplus.readthedocs.io/en/stable/swagger.html
• http://michal.karzynski.pl/blog/2016/06/19/building-beautiful-restful-apis-using-flask-swagger-ui-flask-restplus/