Support Apache Avro data types in AtlasMap

If we want to have a data mapping connector for the managed kafka service we'll shortly need to support some more messaging specific data formats. This issue is to track implementing support for mapping data using the Avro data format.

Avro uses json schema to define it's data types, so most likely a lot of the work to support this would be in the connector layer around atlasmap to ensure the connector supplies the correct document to atlasmap at design/run time.