Add graphql like selector to make in-depth access easier

[trenoncourt]

Imagine you want to make some in-depth access today you will write something like this:

select=id,name,product.id,product.color,product.category.id,product.category.name,product.category.kind

we need to simplify access with a new way of selection :

select=id,name,product(id,color,category(id,name,kind))

The old way will continue to work