update module to support config for innerHtml

Add boolean property wrapInnerHTML to drupal module, as shown in this example: https://jsfiddle.net/g1e7o364/

The guidance for the property can be as follows from our documentation (https://www.civicuk.com/cookie-control/documentation):

The title on the Cookie Control banner has become a H1 title for accessibility reasons. In some cases this might affect SEO. If you want to change it to another heading level, setting wrapInnerHTML: true will set all semantic markup like h1 or p to div elements.