Migrate netlify-cms-www site into this repo (#860)

* Add frontmatter to docs files (prep to move)

* Move docs into position for website migration

* Migrate website from netlify-cms-www

Some modifications, including most of the changes in https://github.com/netlify/netlify-cms-www/pull/58 (previously reverted).

Also updated the readme and added hugo-bin for quicker onboarding of new docs contributors.

* Remove netlify.toml

This allows separate build commands for cms-demo and netlifycms.org.

* Remove website/netlify.toml

May re-add later, but it's not doing anything for now.

* Remove unused content file

website/README.md

@@ -0,0 +1,19 @@
+# Netlify CMS Website & Docs
+
+This directory builds netlifycms.org. If you'd like to propose changes to the site or docs, you'll find the source files in here.
+
+## Local development
+
+The site is built with [Hugo](https://gohugo.io/), managed as an npm dependency via [hugo-bin](https://www.npmjs.com/package/hugo-bin). 
+
+To run the site locally, you'll need to have [Node](https://nodejs.org) and [Yarn](https://yarnpkg.com/en/) installed on your computer.
+
+From your terminal window, `cd` into the `website` directory of the repo, and run
+
+```bash
+yarn
+yarn start
+```
+
+Then visit http://localhost:3000/ - BrowserSync will automatically reload CSS or
+refresh the page when stylesheets or content changes.