Compress the output file (variant query command line)

[jtarraga]

Currently, the results from the variant query command line are stored using the default compression in format Avro, Parquet or JSON. The command line should allow users to select the compression method. The output filename extension indicates the output format and compression. So, "gzip" for deflate/zip compression, "snz" for snappy compression.

Some examples:
./build/bin/hpg-bigdata-local.sh variant query --i test.avro --o test.json.snz ....
./build/bin/hpg-bigdata-local.sh variant query --i test.avro --o test.parquet.gzip ...