Add guide for CDN, menu reorg

doc/cdn/ThemingDoc.vue

@@ -0,0 +1,20 @@
+<template>
+    <DocSectionText v-bind="$attrs">
+        <p>Include the theme file with a link element, see <NuxtLink to="/theming/#themes">themes</NuxtLink> section for the complete list of available themes to choose from.</p>
+    </DocSectionText>
+    <DocSectionCode :code="code" hideToggleCode hideCodeSandbox hideStackBlitz />
+</template>
+
+<script>
+export default {
+    data() {
+        return {
+            code: {
+                basic: `
+<link rel="stylesheet" href="https://unpkg.com/primevue/resources/themes/lara-light-green/theme.css" />
+`
+            }
+        };
+    }
+};
+</script>