Add Granian to Django deployment documentation (ASGI & WSGI support)

[JaeHyuckSa]

Granian, a Rust-based high-performance application server, now provides stable support for running Django through both ASGI and WSGI interfaces.

Django’s current deployment documentation lists Daphne, Uvicorn, and Hypercorn for ASGI, and Gunicorn for WSGI. Since Granian fully supports both interfaces and is being actively adopted, adding it to the documentation would help keep the deployment guide up to date.

Proposed additions:

1. ASGI example:

granian --interface=asgi config.asgi:application

2. WSGI example:

granian --interface=wsgi config.wsgi:application

Even a short note such as:
“Other servers such as Granian also support running Django via ASGI and WSGI.”
would provide helpful guidance to users exploring deployment options.

Forum discussion (includes positive community feedback):
​https://forum.djangoproject.com/t/add-granian-to-how-to-deploy-docs-asgi-wsgi-support/43386

Relevant GitHub discussion:
​https://github.com/emmett-framework/granian/discussions/187

[Adam Johnson]

Let's not do a "short note", but give it similar treatment to existing servers, with a short tutorial for getting deployment statred. For the current document structure, that would mean two documents: one in the ASGI and one in the WSGI directory, within docs/howto/deployment.