…flag)

- Delete `content_server.use_view` waffle flag in favor of always using
  view.
- Delete the husk of `StaticContentServerMiddleware` and references to it.
- Update views module docstring.

This is the first commit of a change/refactor series.

Minimal adjustment of affected import paths, no lint cleanup.

This is the second commit in a refactor/change series.

- Remove `wrong-import-order` amnesty comments
- Run `isort` on the directory

This is the third and last commit in a refactor/change series.