Support PROTOBUF Record Serialization/deserialization

Instead of creating a protobuf converter processor, if PROTOBUF was supported as a valid deserializer in nifi, with the corresponding support underneath, then all the existing record processors would just work and there would be a lot of functionality.

The first pass of this would not necessarily have to infer schema.

I think that a schema can only be avro however, I'm not sure how that is overcome.