Replace local operation with injected

[GustavoCaso]

Fixes #75

@timriley I introduce the concept of Operation.source to know where the operation comes, that way we can modify the way we resolve_operation

Since we want to have different behavior if the operation was injected or extracted from the container

I will add specs but I wanted to share with you before continuing more with this approach

[GustavoCaso]

@timriley I replace the logic to decide if the operation source is from the container or is injected, I think looks much cleaner and makes sense that the Step is the one knowing it. What I haven't quite figure out is how to deal with the difference in the order of the conditions depending on the type of source so far I went with polymorphism. If you have any suggestion please let's discuss it 😄

[timriley]

Resolved in #109