Add a website README (#737)

Also nuke a CloudFront ID that isn't applicable to the Corso website

## Description

Adds a README for building the Corso website

## Type of change

Please check the type of change your PR introduces:
- [x] 🗺️ Documentation

website/Makefile

@@ -22,4 +22,4 @@ publish: build
 
 sync:
 	aws s3 sync /usr/src/website/dist/ s3://corsobackup.io/ --exclude ".git/*" --delete
-	aws cloudfront create-invalidation --distribution-id ESFSMEIU1TDEN --paths "/*"
+	aws cloudfront create-invalidation --distribution-id XXXXX --paths "/*"

website/README.md

@@ -0,0 +1,40 @@
+# Corso website documentation
+
+## Requirements
+
+Building the Corso website requires the following tools on your machine:
+
+- `make`
+- Docker
+
+## Installation
+
+```bash
+make buildimage
+```
+
+## Live documentation development
+
+```bash
+make dev
+```
+
+This command starts a local development server within the Docker container and will expose a live website preview at [http://localhost:3000](http://localhost:3000).
+
+## Building a static website
+
+```bash
+make build
+```
+
+This command generates static content into the `dist` directory for integration with any static contents hosting service. If you are using AWS S3 + CloudFront, you can run `make publish` to upload to the configured S3 bucket.
+
+## Website platform development
+
+```bash
+make shell
+```
+
+Use this command to interactively (and temporarily!) change the contents or
+configuration of the live website container image (for example, when
+experimenting with new packages).