Provide example to write/save your own object (without thrift, avro, protoc)

I am studying parquet and found that it is not so easy to grasp the basic mechanism for writing/reading your own objects to a parquet file when you are not using protocol buffer, avro or thrift.

So my wish is to have a module that cover this topic.
I think for educational purposes it may have some value as it would help people get into the code.

I did the exercice, the code is here:
https://github.com/nromanetti/parquet-mr/tree/master/parquet-manual

**Reporter**: [Nicolas Romanetti](https://issues.apache.org/jira/secure/ViewProfile.jspa?name=nicolasr)

_{**Note**: *This issue was originally created as [PARQUET-420](https://issues.apache.org/jira/browse/PARQUET-420). Please see the [migration documentation](https://issues.apache.org/jira/browse/PARQUET-2502) for further details.*}

Commencez par examiner l’exemple de parquet-manual lié dans l’issue et comparez-le à la structure actuelle de parquet-java. Identifiez où un module pédagogique ou un exemple pourrait être placé, et considérez l’issue comme terminée lorsqu’elle démontre clairement l’écriture et la lecture d’objets personnalisés sans Thrift, Avro ni Protocol Buffers.

Rédigé par le modèle d'indexation à partir du texte de l'issue.