Add a switcher to cast boolean attributes as integer

[afirlejczyk]

Attributes which are using Magento\Catalog\Model\Product\Attribute\Source\Boolean source model has type boolean in ES (true/false values).

Add switcher to configuration to cast attributes as integer (0/1) instead of (true/false) https://github.com/DivanteLtd/vue-storefront/pull/3816