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.*}

首先查看 issue 中链接的 parquet-manual 示例，并将其与当前的 parquet-java 布局进行比较。确定教育模块或示例应放置的位置，并在其清楚演示如何在不使用 Thrift、Avro 或 Protocol Buffers 的情况下写入和读取自定义对象时，认为该 issue 已完成。

由索引模型根据 Issue 内容生成。