Add guide for CDN, menu reorg

doc/csslayer/BootstrapDoc.vue

@@ -0,0 +1,23 @@
+<template>
+    <DocSectionText v-bind="$attrs">
+        <p>Bootstrap has a <i>reboot</i> utility to reset the CSS of the standard elements. If you are including this utility, you may give it a layer while importing it.</p>
+        <DocSectionCode :code="code" hideToggleCode hideCodeSandbox hideStackBlitz />
+    </DocSectionText>
+</template>
+
+<script>
+export default {
+    data() {
+        return {
+            checked: false,
+            code: {
+                basic: `
+@layer bootstrap-reboot, primevue;
+
+@import "bootstrap-reboot.css" layer(bootstrap-rebooot);
+`
+            }
+        };
+    }
+};
+</script>