* turn article.scss into a module + componentized
* Update Survey to use only component styles, add cancel button
* Update GenericError + 404 page to use only standard classes
* update LearningTrack to not use markdown-body
* remove / consolidate stylesheets
* cleanup Graphiql explorer page and scss
* Componentize Breadcrumb styles
* Componentize DeprecationBanner styles
* scope h2 a link style to markdown-body
* cleanup nav, organize page-header and page-footer components
* remove unused scroll-button.scss
* organize LanguagePicker and ProductPicker
* add declarations file
* remove featured-links.scss, update tests
* update list utility and toc test
* fix bad merge resolution
* update breadcrumbs test
