Migrate preview and docs packages from Eleventy to Astro (#2694)

Co-authored-by: Bartek <xbartoszdobija@gmail.com>

preview/pages/layout-horizontal.astro

@@ -0,0 +1,16 @@
+---
+// Port of preview/pages/layout-horizontal.html (layout: homepage)
+import DefaultLayout from '@shared/layouts/DefaultLayout.astro';
+import HomepageContent from '@shared/components/HomepageContent.astro';
+---
+
+<DefaultLayout
+	title="Dashboard"
+	pageHeader="Horizontal layout"
+	pretitle="Overview"
+	actions="buttons"
+	pageMenu="layout.horizontal"
+	pageLibs={['apexcharts', 'jsvectormap']}
+>
+	<HomepageContent />
+</DefaultLayout>