Add option to exclude /tailwind route + associated resources

[samselikoff]

EC-Tailwind ships with some stuff to build an autogenerated /tailwind route, to use during development.

We should add a shouldIncludeStyleguide option that, when false, removes this stuff, and default it to false in prod and true otherwise.

• don't app.import('etw.css')
• don't ship the components/controllers/etc. code used for the styleguide