Introduce functional deps

[maldoinc]

They can ask for dependencies as usual and return a function that will perform the task.

@container.functional
def greeter_factory(translator_service: TranslatorService, other_service ...) -> Callable...
    def greeter(name: str, locale: str = 'en_GB') -> str:
        return ...

    return greeter

@container.autowire
def target(greeter: Annotated[Callable..., Wire(fn=greeter_factory))
    ...

[maldoinc]

This is doable now via factories. Ticket is about updating docs.

from typing_extensions import Protocol


class Greeter(Protocol):
    def __call__(self, name: str) -> str:
        raise NotImplementedError


@service
def greeter_factory() -> Greeter:
    def _greeter(name: str) -> str:
        return f"Hi {name}"

    return _greeter


def target(greeter: Greeter) -> None: ...