feat(component): add Notification

Closes #20

src/components/Notification/NotificationButton.svelte

@@ -0,0 +1,36 @@
+<script>
+  let className = undefined;
+  export { className as class };
+  export let notificationType = 'toast';
+  export let type = 'button';
+  export let iconDescription = 'close icon';
+  export let renderIcon = Close20;
+  export let title = undefined;
+  export let style = undefined;
+
+  import Close20 from 'carbon-icons-svelte/lib/Close20';
+  import { cx } from '../../lib';
+
+  const _class = cx(
+    notificationType === 'toast' && '--toast-notification__close-button',
+    notificationType === 'inline' && '--inline-notification__close-button',
+    className
+  );
+  const _iconClass = cx(
+    notificationType === 'toast' && '--toast-notification__close-icon',
+    notificationType === 'inline' && '--inline-notification__close-icon'
+  );
+</script>
+
+<button
+  on:click
+  on:mouseover
+  on:mouseenter
+  on:mouseleave
+  aria-label={iconDescription}
+  title={iconDescription}
+  class={_class}
+  {style}
+  {type}>
+  <svelte:component this={renderIcon} class={_iconClass} {title} />
+</button>