Add a static site generator

There is no build for the element or site utilities like PrismJS yet, so this site only works locally at the moment.

docs-src/_includes/nav.11ty.cjs

@@ -0,0 +1,9 @@
+module.exports = function(data) {
+  return `
+<nav>
+  <a href="/docs/">Home</a>
+  <a href="/docs/examples/">Examples</a>
+  <a href="/docs/api/">API</a>
+  <a href="/docs/install/">Install</a>
+</nav>`;
+};