Add Mockup browser component (#3276)

screenshots/pages/mockup-browser.astro

@@ -0,0 +1,13 @@
+---
+// Mockup browser on its own, no card: one frame with the lock icon and the
+// Tabler dashboard screenshot, light and dark through the hide-theme classes.
+import ScreenshotLayout from '../layouts/ScreenshotLayout.astro'
+import MockupBrowser from '@ui/MockupBrowser.astro'
+---
+
+<ScreenshotLayout title="Mockup browser" columns={2}>
+  <MockupBrowser url="https://preview.tabler.io" secure>
+    <img src="/static/tabler-preview@2x.png" class="hide-theme-dark" alt="" />
+    <img src="/static/tabler-preview-dark@2x.png" class="hide-theme-light" alt="" />
+  </MockupBrowser>
+</ScreenshotLayout>