Could you please add ORJSON support for high performance?

[accredited-unicorn]

I'm suggesting that Ariadne borrow a snippet of performance enhancing code from FastAPI...

try:
    import orjson
except ImportError:  # pragma: nocover
    orjson = None  # type: ignore


class ORJSONResponse(JSONResponse):
    media_type = "application/json"

    def render(self, content: Any) -> bytes:
        assert orjson is not None, "orjson must be installed to use ORJSONResponse"
        return orjson.dumps(content)

ORJSON has been benchmarked to reduce framework overhead, and it has been benchmarked to increase throughout on batches of multiple queries. Replacing the default json library with orjson resulted in multiple query throughput that beat Uvicorn, Starlette, and vanilla FastAPI.

The snipped above should also enhance Ariadne's performance in a meaningful and measurable way.

[rafalp]

We already have PR that adds optional support for customizable JSON library: #650