feat: button group

docs/guide/buttonGroup/examples/ButtonGroupBasicExample.vue

@@ -0,0 +1,11 @@
+<template>
+  <button-group>
+    <Button>hello world</Button>
+    <Button color="purple">hello world</Button>
+    <Button color="alternative">hello world</Button>
+    <Button color="red">hello world</Button>
+  </button-group>
+</template>
+<script setup>
+import { ButtonGroup, Button } from '../../../../src/index'
+</script>