ParquetMetadata.fromJSON method doesn't work

I wrote a simple testCase to test the fromJSON method below and it fails because ParquetMetadata does not implement default constructors.

```

@Test public void testFromJSON() {
MessageType schema = parseMessageType("message test { optional binary some_null_field; }");
parquet.hadoop.metadata.FileMetaData fileMetaData =
new parquet.hadoop.metadata.FileMetaData(schema, new HashMap(), null);
List blockMetaDataList = new ArrayList();
BlockMetaData blockMetaData = new BlockMetaData();
blockMetaData.addColumn(createColumnChunkMetaData());
blockMetaDataList.add(blockMetaData);
ParquetMetadata metadata = new ParquetMetadata(fileMetaData, blockMetaDataList);

String metadataStr = ParquetMetadata.toJSON(metadata);
System.out.println(ParquetMetadata.toPrettyJSON(metadata));
ParquetMetadata m2 = ParquetMetadata.fromJSON(metadataStr);
}
```

**Reporter**: [Vihang Karajgaonkar](https://issues.apache.org/jira/secure/ViewProfile.jspa?name=vihangk1)

_{**Note**: *This issue was originally created as [PARQUET-851](https://issues.apache.org/jira/browse/PARQUET-851). Please see the [migration documentation](https://issues.apache.org/jira/browse/PARQUET-2502) for further details.*}