Thumbnail molecule to print boxes with image, headline, text and button.

* **thumbnails** (Array)
_Supported values:_ An array containing headline atom object, text and button object.
* **thubnails.headline** (Object)
_Supported values:_ The headline object supports the `text` property containing the headline content.
* **thubnails.text** (String)
_Supported values:_ The text to be added to thumbnail molecule.
* **thubnails.button** (Object)
_Supported values:_ The button object has the same properties supported by `atoms/text/link`.
