Automatically set spark.sql.parquet.writelegacyformat; When using bulkinsert to insert data which contains decimal Type.

Now by default ParquetWriteSupport will write DecimalType to parquet as int32/int64 when the scale of decimalType < Decimal.MAX_LONG_DIGITS(),
but AvroParquetReader which used by HoodieParquetReader cannot support read int32/int64 as DecimalType. this will lead follow error

Caused by: java.lang.UnsupportedOperationException: org.apache.parquet.column.values.dictionary.PlainValuesDictionary$PlainIntegerDictionary
    at org.apache.parquet.column.Dictionary.decodeToBinary(Dictionary.java:41)
    at org.apache.parquet.avro.AvroConverters$BinaryConverter.setDictionary(AvroConverters.java:75)
    ......