Use lozad for lazy image loading

Ref: grouped-emoji-picker

src/directives/lazy_image_container.js

@@ -0,0 +1,13 @@
+
+import lozad from 'lozad'
+
+const LazyImageContainer = {
+  inserted (el) {
+    const images = el.querySelectorAll('img')
+    console.log(images.length)
+    el.$observer = lozad(images)
+    el.$observer.observe()
+  }
+}
+
+export default LazyImageContainer