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/MultiSelect/MultiSelect.Story.svelte

@@ -1,22 +1,21 @@
 <script>
-  import Layout from '../../internal/ui/Layout.svelte';
-  import Button from '../Button';
-  import MultiSelect from './MultiSelect.svelte';
+  import Layout from "../../internal/ui/Layout.svelte";
+  import { Button } from "../Button";
+  import MultiSelect from "./MultiSelect.svelte";
 
-  let value = '';
-
-  let items = [
-    { id: 'option-0', text: 'Option 1' },
-    { id: 'option-1', text: 'Option 2' },
-    { id: 'option-2', text: 'Option 3' },
-    { id: 'option-3', text: 'Option 4' },
+  $: value = "";
+  $: selectedIds = [];
+  $: items = [
+    { id: "option-0", text: "Option 1" },
+    { id: "option-1", text: "Option 2" },
+    { id: "option-2", text: "Option 3" },
+    { id: "option-3", text: "Option 4" },
     {
-      id: 'option-4',
-      text: 'An example option that is really long to show what should be done to handle long text'
+      id: "option-4",
+      text:
+        "An example option that is really long to show what should be done to handle long text"
     }
   ];
-
-  let selectedIds = [];
 </script>
 
 <Layout>