feat(components): add Tabs

Closes #32

src/components/Tabs/TabsSkeleton.svelte

@@ -0,0 +1,25 @@
+<script>
+  let className = undefined;
+  export { className as class };
+  export let style = undefined;
+
+  import { cx } from '../../lib';
+
+  const _class = cx('--tabs', '--skeleton', className);
+</script>
+
+<div on:click on:mouseover on:mouseenter on:mouseleave class={_class} {style}>
+  <div class={cx('--tabs-trigger')}>
+    <div class={cx('--tabs-trigger-text')}>&nbsp;</div>
+    <svg width="10" height="5" viewBox="0 0 10 5" fillRule="evenodd">
+      <path d="M10 0L5 5 0 0z" />
+    </svg>
+  </div>
+  <ul class={cx('--tabs__nav', '--tabs__nav--hidden')}>
+    {#each [0, 1, 2, 3] as item, i (item)}
+      <li class={cx('--tabs__nav-item')}>
+        <div class={cx('--tabs__nav-link')}>&nbsp;</div>
+      </li>
+    {/each}
+  </ul>
+</div>