xmlObject fields updates

[baywet]

OAI 3.2.0 makes a few updates to the XML object

• Add a new enum named OpenApiXmlNodeType (element, attribute, text, cdata, or none)
• Add a new property called NodeType
• Mark the Attribute property as obsolete
• Make the Attribute property getter evaluate whether the NodeType property is set to attribute
• Make the Attribute property setter set the NodeType property to attribute when true, none when false
• DO NOT serialize the attribute property in 3.2.0, but serialize it in 3.1.0
• Mark the Wrapped property as obsolete
• Make the Wrapped property getter evaluate whether NodeType is set to element
• Make the Wrapped property setter set the NodeType property to element when true, none when false
• DO NOT serialize the wrapped property in 3.2.0, but serialize it in 3.1.0
• DO NOT serialize the NodeType property in 3.1.0 or below.