Minimize surface area (part 2)

As @dreedy pointed out via a slack message, when we include Scientist::Experiment it overwrites the default class that you get if you attempt to run the science method.

His feedback was that this could be viewed as confusing and that's really valuable developer feedback. Part of the process of minimizing the surface area and improving the visible aspects of experiment.rb was to pull these concerns into the BaseInterface module. Since the default class can't be a module (where we'd move the include statement to), we need to address it now, both to reduce confusion, and also not break it when moving it into the module.

This is really the only way I was able to find that allows us to circumvent the way that scientist changes the default class.