refactor: move test/ and yarn to repo root

Also lint and format entire repo, beyond just wowchemy/ dir

URL encode `(` and `)` in `[#MadeWithWowchemy](...(..)...)` in Readme.md for Prettier

test/content/home/index.md

@@ -0,0 +1,4 @@
+---
+type: widget_page
+headless: true
+---

test/content/home/section.md

@@ -0,0 +1,9 @@
+---
+widget: blank
+headless: true
+weight: 1
+design:
+  columns: '1'
+---
+
+Hello world 😃