Add optional CORS headers

[BSchilperoort]

To be able to communicate with a RemoteBMI server through the browser (e.g. a javascript frontend), users need to be able to add CORS headers to the servers.

To add to;

• Python
• Julia
• R

[BSchilperoort]

For python use

from starlette.middleware.cors import CORSMiddleware
from connexion.middleware import MiddlewarePosition

...
    app.add_middleware(
        CORSMiddleware,
        allow_origins=["*"],
        position=MiddlewarePosition.BEFORE_EXCEPTION,
        allow_credentials=True,
        allow_methods=["*"],
        allow_headers=["*"],
    )