feat: ASGI support

[Lancetnik]

Description

It just a minimal ASGI support to make FastStream able to serve ASGI endpoints and be runned by uvicorn or any other server.

Implementation is very limited and was created to provides users with a basic functional for metrics, documentation, readi- and liveness probes hosting.

from faststream.nats import NatsBroker
from faststream.asgi import AsgiFastStream, make_ping_asgi

from prometheus_client import make_asgi_app
from prometheus_client.registry import CollectorRegistry

broker = NatsBroker()

prometheus_registry = CollectorRegistry()

app = AsgiFastStream(
    broker,
    asyncapi_path="/docs",
    asgi_routes=[
        ("/health", make_ping_asgi(broker, timeout=5.0)),
        ("/metrics", make_asgi_app(registry=prometheus_registry))
    ]
)

uvicorn main:app

Close #1181, close #1638, close #1647

Type of change

Please delete options that are not relevant.

• Documentation (typos, code examples, or any documentation updates)
• Bug fix (a non-breaking change that resolves an issue)
• New feature (a non-breaking change that adds functionality)
• Breaking change (a fix or feature that would disrupt existing functionality)
• This change requires a documentation update

Checklist

• My code adheres to the style guidelines of this project (scripts/lint.sh shows no errors)
• I have conducted a self-review of my own code
• I have made the necessary changes to the documentation
• My changes do not generate any new warnings
• I have added tests to validate the effectiveness of my fix or the functionality of my new feature
• Both new and existing unit tests pass successfully on my local environment by running scripts/test-cov.sh
• I have ensured that static analysis tests are passing by running scripts/static-analysis.sh
• I have included code examples to illustrate the modifications

[Lancetnik]

@kumaranvpl did you read [ASGI](getting-started/asgi.md) page?

[kumaranvpl]

@Lancetnik I didn't. I will do it later today.