Configurable context pattern

[aaronmallen]

Elevator pitch, describe and sell us your feature request

As a developer,
I want to be able to configure which context pattern I want to use
so that Rails generators don't generate unnecessary classes if I don't want to use them.

Is your feature request related to a problem

It's frustrating that the generators automatically create context classes for me when I wish to use the interactor only pattern i.e.:

class MyInteractor < ApplicationInteractor
  context_attributes ...
  context_validates ...
end