Thrift binary fields are not serialized correctly

Thrift binary fields are not serialized correctly - I believe UTF-8 encoding is applied.

A demonstration of this bug is shown in https://github.com/laurencer/parquet-mr-bug

This appears to be an issue in Parquet-MR where Thrift TType is used determine the type of fields. TType actually represents the on-disk/encoded field type tag - that does not distinguish between binary and string fields.

String data is not actually represented on-disk as being different - instead it is up to the program to interpret the binary data as a UTF-8 encoded string. Parquet-MR instead assumes that every binary field is a UTF-8 encoded string.

This may have arisen because the binary field tag is actually TType.String (where it actually just represents a raw binary field).

**Reporter**: [Laurence Rouesnel](https://issues.apache.org/jira/secure/ViewProfile.jspa?name=laurencer)

_{**Note**: *This issue was originally created as [PARQUET-158](https://issues.apache.org/jira/browse/PARQUET-158). Please see the [migration documentation](https://issues.apache.org/jira/browse/PARQUET-2502) for further details.*}

Beginne mit der verknüpften parquet-mr-bug-Demonstration und verfolge, wie Parquet-MR mit Thrift TType.String für Binärfelder umgeht. Bestätige, an welcher Stelle Binärdaten als UTF-8 interpretiert werden, und vergleiche diesen Pfad mit String-Feldern. Als abgeschlossen gilt die Aufgabe, wenn rohe Binärfelder ohne UTF-8-Interpretation serialisiert und deserialisiert werden, während String-Felder ihr erwartetes Verhalten beibehalten.

Vom Indexierungsmodell aus dem Issue-Text verfasst.