Allow AsyncFactory provider to resolve sync creators.

[xelandernt]

Problem:

class MyClass: ...

class Container(BaseContainer):
    p = providers.AsyncFactory(MyClass)

await Container.p.resolve() # raises

Often, initiating MyClass might require an async dependency (in which case Factory cannot be used)

Solution:

• Allow AsyncFactory to accept sync creators.
• Still only allow resolution of async Factory using resolve()