feat: button loading, disabled(WIP), refactor to useButtonClasses, Spinner and vitest

docs/guide/button/examples/ButtonDisabledExample.vue

@@ -0,0 +1,15 @@
+<template>
+  <div class="inline-flex align-center gap-2 flex-wrap">
+    <Button color="default" disabled>Default</Button>
+    <Button color="alternative" disabled>Alternative</Button>
+    <Button color="dark" disabled>Dark</Button>
+    <Button color="light" disabled>Light</Button>
+    <Button color="green" disabled>Green</Button>
+    <Button color="red" disabled>Red</Button>
+    <Button color="yellow" disabled>Yellow</Button>
+    <Button color="purple" disabled>Purple</Button>
+  </div>
+</template>
+<script setup>
+import { Button } from '../../../../src/index'
+</script>