pullquote quill format

pullquote.js

{
  type: 'embed',
  tag: 'IFRAME',
  add: function(node, data) {
    node.classList.add('pullquote');
    node.setAttribute('data-pullquote', data.value);
    node.setAttribute('src', '/iframe/pullquote.html');
    return node;
  },
  remove: function(node) {
    node.classList.remove('pullquote');
    node.removeAttribute('data-pullquote');
    node.setAttribute('src', '/iframe/pullquote.html');
    return node;
  },
  value: function(node) {
    return { value: node.dataset.pullquote };
  },
  match: function(node) {
    return node.tagName === 'IFRAME' && node.classList.contains('pullquote');
  }
}