Add sandbox project using Contentful CMS

I used the boilerplate/typescript project as a starting point. This project
fetches and renders books that I'm defining in a Contentful CMS that I created.

website/sandbox/contentful/postcss.config.js

@@ -0,0 +1,7 @@
+const tailwindcss = require('tailwindcss')
+
+module.exports = {
+  plugins: [
+    tailwindcss('./tailwind.config.js')
+  ]
+}