feat(component): add Notification

Closes #20

src/components/Notification/NotificationActionButton.svelte

@@ -0,0 +1,22 @@
+<script>
+  let className = undefined;
+  export { className as class };
+  export let style = undefined;
+
+  import Button from '../Button';
+  import { cx } from '../../lib';
+
+  const _class = cx('--inline-notification__action-button', className);
+</script>
+
+<Button
+  kind="ghost"
+  size="small"
+  on:click
+  on:mouseover
+  on:mouseenter
+  on:mouseleave
+  class={_class}
+  {style}>
+  <slot />
+</Button>