feat: Documentation and API reference (#348)

Co-authored-by: Vadim Smirnov <smirnou.vadzim@gmail.com>
Co-authored-by: zakariasaad <zakaria.elas@gmail.com>
Co-authored-by: Vilfred Sikker <vilfredsikker@gmail.com>
Co-authored-by: Kasper <kasper@medusa-commerce.com>
Co-authored-by: Sebastian Rindom <skrindom@gmail.com>
Co-authored-by: Kasper Fabricius Kristensen <45367945+kasperkristensen@users.noreply.github.com>

www/package.json

@@ -0,0 +1,11 @@
+{
+  "name": "www",
+  "version": "0.0.0",
+  "description": "Medusa documentation site",
+  "main": "index.js",
+  "license": "MIT",
+  "dependencies": {
+    "execa": "^5.1.1",
+    "gatsby-cli": "^3.11.0"
+  }
+}