@dbu could we maybe have a more generic way to configure a ``FieldMapEnhancer``? ie. where we can define the name of the attribute the enhancer should look for, the name the attribute the enhancer should add along with an arbitrary scalar/array structure to set for a match?

```
generic_field_map_enhancer:
    source: _sylius_class
    target: _sylius
    hashmap:
        Sylius\Bundle\CoreBundle\Model\Product:
            _controller: sylius.controller.product:showAction
            _sylius:
                template: SyliusWebBundle:Frontend/Product:show.html.twig
                criteria: {slug: $slug}
        Sylius\Bundle\CoreBundle\Model\Taxon:
            _controller: sylius.controller.product:indexByTaxonAction
            _sylius:
                template: SyliusWebBundle:Frontend/Product:indexByTaxon.html.twig
```