ISTWCMS-3661: adding styling for facebook

source/_patterns/04-components/facebook/_facebook.scss

+.uw-facebook {
+  width: 100%;
+
+  &__wrapper {
+    margin-left: auto;
+    margin-right: auto;
+    text-align: center;
+  }
+}

source/_patterns/04-components/facebook/facebook.js

+(function ($, Drupal) {
+  'use strict';
+
+  // The styling for this mobile menu is located in source/_patterns/04-components/menus/menu--main/.
+
+  Drupal.behaviors.facebook = {
+    attach(context, settings) {
+      $('.uw-facebook__data').each(function () {
+
+        var fbwidth = $(this).parent().width();
+
+        if (fbwidth == 0) {
+          fbwidth = 239;
+        }
+
+        var fburl = encodeURIComponent('/' + $(this).data('username'));
+
+        $(this).before('<iframe src="https://www.facebook.com/plugins/likebox.php?href=' + fburl + '&amp;width=' + fbwidth + '&amp;height=350&amp;colorscheme=light&amp;show_faces=false&amp;border_color&amp;stream=true&amp;header=true" scrolling="no" frameborder="0" style="border:none; overflow:hidden; max-width: 500px;width:' + fbwidth + 'px; height:350px;" allowTransparency="true"></iframe>');
+        $(this).remove();
+      });
+    },
+  };
+})(jQuery, Drupal);

source/_patterns/04-components/facebook/facebook.twig

+<div class="uw-facebook">
+  <div class="uw-facebook__wrapper">
+    <div class="uw-facebook__data" data-username="{{ username }}">
+    </div>
+  </div>
+</div>