Real field Determinator

[ivan1986]

improvement idea after #1606

Add to Determinator option virtual

If true works as old case, but if false use real field or virtual property
skip

'The discriminator field name "%s" of the base-class "%s" conflicts with a regular property of the sub-class "%s".',

exception and use default serializer of field
in this case makes easy to partially migrate different objects to determinator
classic example is a shopping cart with different types of goods, and only some types of goods have different classes and also reverse unique matching is not required, several types can be handled by one class