Feature/website overhaul (#49)

* Reorganize repo
* Overhaul website design and rewrite in NextJS and Typescript
* Delete website-publish.yml

website/content/docs/test-backend.mdx

@@ -0,0 +1,16 @@
+---
+group: Accounts
+title: Test
+weight: 50
+---
+
+You can use the `test-repo` backend to try out Static CMS without connecting to a Git repo. With this backend, you can write and publish content normally, but any changes will disappear when you reload the page. This backend powers the Static CMS [demo site](https://cms-demo.netlify.com/).
+
+**Note:** The `test-repo` backend can't access your local file system, nor does it connect to a Git repo, thus you won't see any existing files while using it.
+
+To enable this backend, add the following lines to your Static CMS `config.yml` file:
+
+```yaml
+backend:
+  title: test-repo
+```