VectorizedParquetRecordReader doesn't use Parquet's dictionary filtering feature

The VectorizedParquetRecordReader currently only uses statistics filtering, and does not make use of dictionary filtering in Parquet. Having dictionary filtering would be very useful for string/binary columns that have low cardinality

Some relevant code paths:

• https://github.com/apache/spark/blob/master/sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/parquet/ParquetFileFormat.scala#L367-L387 When vectorizedReader is enabled, the code will use VectorizedParquetRecordReader, which uses SpecificParquetRecordReaderBase below
• https://github.com/apache/spark/blob/master/sql/core/src/main/java/org/apache/spark/sql/execution/datasources/parquet/SpecificParquetRecordReaderBase.java#L109 This is where the row group filtering is being performed. It calls the method below
• https://github.com/apache/parquet-mr/blob/apache-parquet-1.8.2/parquet-hadoop/src/main/java/org/apache/parquet/filter2/compat/RowGroupFilter.java#L64-L70

The RowGroupFilter constructor used in Spark's VectorizedParquetRecordReader hard-codes the FilterLevel used to only FilterLevel.STATISTICS, and is deprecated.

  @Deprecated
  private RowGroupFilter(List<BlockMetaData> blocks, MessageType schema) {
    this.blocks = checkNotNull(blocks, "blocks");
    this.schema = checkNotNull(schema, "schema");
    this.levels = Collections.singletonList(FilterLevel.STATISTICS);
    this.reader = null;

Compare this to org.apache.parquet.hadoop.ParquetRecordReader.initialize(), which uses the second RowGroupFilter constructor that allows it to set the FilterLevel. Relevant code here:
https://github.com/apache/parquet-mr/blob/master/parquet-hadoop/src/main/java/org/apache/parquet/hadoop/ParquetRecordReader.java#L166-L182