Template for docs pages

Summary:
- Dynamic loading of documentation pages
- code highlighting for markdown files
- editing playground from sidebar

Reviewed By: emilsjolander

Differential Revision: D6964951

fbshipit-source-id: 1c7f36afa8d23215471d5b9a9c01bd2241c2008e

website/gatsby-node.js

@@ -25,6 +25,7 @@ exports.createPages = ({boundActionCreators, graphql}) => {
             frontmatter {
               path
               hasPlayground
+              editableProperties
             }
             html
           }