Replace the usage of `Any` with generic types

[vdusek]

Do not use Any type as suggested in the ANN401.

Instead of

from typing import Any

def get_first(container: list[Any]) -> Any:
    return container[0]

use the following

from typing import TypeVar

T = TypeVar('T')

def get_first(container: list[T]) -> T:
    return container[0]

Any can probably still make sense for the *args / **kwargs.

[janbuchar]

After #210, I believe the only notable offender is the input shape in Actor.