Move HTML to twig templates

Currently commerce outputs HTML using ['#prefix'] and ['#suffix']. Here are two examples:

CartBlock.php:

$cart_views[] = [
  '#prefix' => '<div class="cart cart-block">',
  '#suffix' => '</div>',
  '#type' => 'view',
  '#name' => $available_views[$cart_id],
  '#arguments' => [$cart_id],
  '#embed' => TRUE,
];

CartController.php:

$build[$cart_id] = [
  '#prefix' => '<div class="cart cart-form">',
  '#suffix' => '</div>',
  '#type' => 'view',
  '#name' => $cart_views[$cart_id],
  '#arguments' => [$cart_id],
  '#embed' => TRUE,
];

As a themer it is hard to get rid of that since there is not template to override and remove the markup. We should introduce twig templates in those cases.