New documentation site and examples app

Replaces the old storybook with static HTML documentation and an interactive
examples app. The documentation is now easier to customize, easier to maintain,
and faster to load. The interactive examples are a dedicated Next.js app that
can be loaded and edited in codesandbox, as well as embedded in the
documentation where needed.

packages/examples/shared/example.js

@@ -0,0 +1,56 @@
+import { StyleSheet, Text, View } from 'react-native';
+
+export default function Example(props) {
+  return (
+    <View style={styles.root}>
+      <View style={styles.header}>
+        <Text accessibilityLabel="Back" href="/" style={styles.back}>
+          <svg
+            style={{ fill: '#555', height: '100%' }}
+            viewBox="0 0 140 140"
+            xmlns="http://www.w3.org/2000/svg"
+          >
+            <path d="M105.614 118.681c3.398 3.396 3.4 8.912 0 12.311-3.396 3.399-8.91 3.398-12.311 0-.02-.02-.035-.04-.053-.061l-.025.022-57.66-57.66.024-.022a8.664 8.664 0 01-2.608-6.208 8.672 8.672 0 013.229-6.762l-.06-.058 57.66-57.66.025.024c.018-.021.033-.039.053-.058A8.706 8.706 0 01106.2 14.86c-.021.02-.041.034-.061.054l.023.024-52.119 52.125 51.54 51.54-.025.021c.015.022.036.036.056.057" />
+          </svg>
+        </Text>
+        <Text accessibilityRole="heading" style={styles.title}>
+          {props.title}
+        </Text>
+      </View>
+      <View style={styles.container}>
+        {props.children}
+      </View>
+    </View>
+  );
+}
+
+const styles = StyleSheet.create({
+  root: {
+    height: '100vh',
+  },
+  header: {
+    paddingVertical: '1em',
+    borderBottomColor: '#ccc',
+    borderBottomWidth: 1,
+  },
+  title: {
+    fontSize: 18,
+    fontWeight: 'bold',
+    textAlign: 'center'
+  },
+  back: {
+    position: 'absolute',
+    height: '100%',
+    display: 'flex',
+    padding: 10,
+    left: 0,
+    top: 0,
+    width: 40,
+    alignItems: 'center',
+  },
+  container: {
+    alignItems: 'center',
+    flex: 1,
+    overflowY: 'scroll'
+  }
+});