handle JsonNodes as arguments for default values in FieldBuilders

[radai-rosenblatt]

otherwise:

Unknown datum class: class com.fasterxml.jackson.databind.node.IntNode
org.apache.avro.AvroRuntimeException: Unknown datum class: class com.fasterxml.jackson.databind.node.IntNode
	at org.apache.avro.util.internal.JacksonUtils.toJson(JacksonUtils.java:96)
	at org.apache.avro.util.internal.JacksonUtils.toJsonNode(JacksonUtils.java:53)
	at org.apache.avro.Schema$Field.<init>(Schema.java:591)
	at com.linkedin.avroutil1.compatibility.avro110.FieldBuilder110.build(FieldBuilder110.java:109)
	at com.linkedin.avroutil1.compatibility.AvroCompatibilityHelper.createSchemaField(AvroCompatibilityHelper.java:1012)
	at com.linkedin.avroutil1.compatibility.AvroCompatibilityHelper.createSchemaField(AvroCompatibilityHelper.java:1016)

ideally we deserialize the json using the schema for the field