[enhancement][docs] aws lambda monolith (lambdalith)

[Lewiscowles1986]

Description

It took me a very, very long time to work out why I could not use Connexion 3 with Flask in AWS Lambda #1807

While some of this may have been docs and other iterations, and workload related (I didn't try for months solid, more like an hour or two here, and there)

In case anyone is interested or would like docs

app.py

from connexion import FlaskApp

app = FlaskApp(__name__)

app.add_api("openapi.yaml")


def post_greeting(name: str):
    return f"Hello {name}", 200

lambda_handler.py

from app import app
from mangum import Mangum

lambda_handler = Mangum(app, lifespan="off")

Essentially, use Mangum man·gumm (not Magnum mag·nuhm) is the only thing you'll need. Prior we used some AWS to wsgi package, but Connexion 3 is essentially, always ASGI on the outside.

I Think this also helps if refactoring.