This change makes it so that instead of ReviewBoxListView inspecting the DOM

and creating models and views to go along with it, those models and views are

created directly with the appropriate data. After this, ReviewBoxListView was

pretty useless, and because ReviewRequestPageView already had its fingers in

the pie, I've just moved all its functionality into there.

Ran js-tests.
Smoke tested the review request detail page with multiple reviews and change

  description boxes.