Support retaining of XML attribute-ness with `JsonNode`

Hi!
I've faced an issue working with XML documents (deserialization, modifying, serialization): from JsonNode I can't serialize XML with attributes. Attributes become regular JsonNode fields after deserialization and then serialized as child tags.
Kindly asking to consider adding new Feature (both for deserialization and serialization, disabled by default) to mark attribute field names with special prefix symbol (for example ampersand or underscore if ampersand may break something) during deserialization and, if new Feature enabled, serialize fields with this prefix to XML as attributes of parent tag (removing prefix before serialization), not as child tags.