refactor: use $$restProps API

- add ref prop for applicable components (#196)
- add slot to Content Switcher `Switch` component (#183)
- remove fillArray, css utilities

src/components/Dropdown/Dropdown.Skeleton.svelte

@@ -1,20 +1,19 @@
 <script>
-  let className = undefined;
-  export { className as class };
   export let inline = false;
-  export let style = undefined;
-
-  import { cx } from '../../lib';
 </script>
 
 <div
+  class:bx--skeleton={true}
+  class:bx--dropdown-v2={true}
+  class:bx--list-box={true}
+  class:bx--form-item={true}
+  class:bx--list-box--inline={inline}
+  {...$$restProps}
   on:click
   on:mouseover
   on:mouseenter
-  on:mouseleave
-  class={cx('--skeleton', '--dropdown-v2', '--list-box', '--form-item', inline && '--list-box--inline', className)}
-  {style}>
-  <div role="button" class={cx('--list-box__field')}>
-    <span class={cx('--list-box__label')} />
+  on:mouseleave>
+  <div role="button" class:bx--list-box__field={true}>
+    <span class:bx--list-box__label={true} />
   </div>
 </div>