feat: refine sidenav and layout demo, update veui

one/docs/demo/sidenav/normal.vue

@@ -0,0 +1,84 @@
+<template>
+<article>
+  <veui-sidenav :items="items"/>
+</article>
+</template>
+
+<script>
+import { Sidenav } from 'veui'
+
+export default {
+  name: 'veui-sidenav-demo',
+  components: {
+    'veui-sidenav': Sidenav
+  },
+  data () {
+    let items = [
+      {
+        label: 'Group One',
+        name: 'group-one',
+        children: [
+          {
+            label: 'Sub One',
+            name: 'sub-one',
+            children: [
+              {
+                label: 'Input',
+                to: '/components/input'
+              }
+            ]
+          },
+          {
+            label: 'Loading',
+            name: 'Loading',
+            to: '/components/loading',
+            children: [
+              {
+                label: 'Switch',
+                to: '/components/switch'
+              }
+            ]
+          }
+        ]
+      },
+      {
+        label: 'Button',
+        name: 'Button',
+        to: '/components/button',
+        children: [
+          {
+            label: 'Disabled',
+            name: 'Disabled',
+            disabled: true,
+            children: [
+              {
+                label: 'Link',
+                name: 'Link',
+                to: '/components/link'
+              }
+            ]
+          }
+        ]
+      },
+      {
+        label: 'Navigation Three',
+        name: 'nav-three',
+        disabled: true
+      },
+      {
+        label: 'Navigation Four',
+        name: 'nav-four',
+        children: [
+          {
+            label: 'Progress',
+            to: '/components/progress'
+          }
+        ]
+      }
+    ]
+    return {
+      items
+    }
+  }
+}
+</script>