Add a full width utility class for media

[Demotive]

Allow media such as images to break horizontally out of the grid.

Add to a lone element (ie img) or a container (ie figure) -

<figure class="app-media--full-width">
  <img src="prototype-flow.png" alt="Diagram depicting the prototype user journey using sequential screen grabs from left to right.">
  <figcaption>The prototype journey from left to right, from calculator result to a 'finding services' loading screen.</figcaption>
</figure>

<figure class="app-media--full-width">
  <img src="prototype-flow.png" alt="Diagram depicting the prototype user journey using sequential screen grabs from left to right.">
</figure>

The .app-media--full-width element with remain at 92vw up to a max of 960px.

[Demotive]

Rebased over the newer application.

Example using nunjucks:

{% from "nhsuk/components/images/macro.njk" import image as nhsukImage %}
{{ nhsukImage({
  classes: "app-media--full-width",
  src: "prototype-flow.png",
  alt: "Diagram depicting the prototype user journey using sequential screen grabs from left to right.",
  caption: "The prototype journey from left to right, from calculator result to a ‘finding services’ loading screen."
}) }}