feat(component): add DatePicker

Closes #15

src/components/DatePicker/DatePicker.Skeleton.svelte

@@ -0,0 +1,21 @@
+<script>
+  let className = undefined;
+  export { className as class };
+  export let id = Math.random();
+  export let range = false;
+  export let style = undefined;
+
+  import { cx, fillArray } from '../../lib';
+</script>
+
+<div on:click on:mouseover on:mouseenter on:mouseleave class={cx('--form-item')} {style}>
+  <div
+    class={cx('--date-picker', '--skeleton', range && '--date-picker--range', !range && '--date-picker--short', !range && '--date-picker--simple', className)}>
+    {#each fillArray(range ? 2 : 1) as input, i (input)}
+      <div class={cx('--date-picker-container')}>
+        <label class={cx('--label')} for={id} />
+        <div class={cx('--date-picker__input', '--skeleton')} />
+      </div>
+    {/each}
+  </div>
+</div>