Add templates that demonstrate move complex Mannequin templates

[rbayliss]

One example would be Rick's Paragraphs template in LastCallMedia/Mannequin#93, but I don't think we want to use Paragraphs as an example here, since it doesn't come installed out of the box. So we could use:

• field.html.twig
• block.html.twig
• page.html.twig
• etc.