Add support for protobuf to parquet-cascading

The parquet-cascading module currently includes code that lets Cascading write and read Thrift-based data to Parquet files. Protobufs is another popular alternative to Thrift which can be explicitly supported by leveraging the existing code in parquet-protobuf.

**Reporter**: [Matt Martin](https://issues.apache.org/jira/secure/ViewProfile.jspa?name=matt.martin) / @matt-martin
**Assignee**: [Matt Martin](https://issues.apache.org/jira/secure/ViewProfile.jspa?name=matt.martin) / @matt-martin

_{**Note**: *This issue was originally created as [PARQUET-93](https://issues.apache.org/jira/browse/PARQUET-93). Please see the [migration documentation](https://issues.apache.org/jira/browse/PARQUET-2502) for further details.*}