split io and manager

[gpetretto]

No description provided.

[davidwaroquiers]

Very good. There are some questions I am raising in the comments (some of them are related to my initial architectural/data structure design).
One of them is still about QResources, whether it should contain everything (and then probably called something else, but that's just a detail), or whether it should "only" contain stuff related to what the user wants as a hardware to run on, while the rest is passed down through something else (another object, or directly in arguments). Also, somehow related, it currently is a dataclass but maybe it is too constraining if we want it to be more extendable in the future (and what we actually get from that in this case is probably not worth it ?). What do you think ?
Other than that, more like cosmetic questions and one or two fixes. Not sure about the ProcessPlacement in the end, which seems more like a constraint rather than a helper (unless we allow to not set it, e.g. set it to None, maybe by default).

[davidwaroquiers]

I think it is ok, we can merge.