Add support for json/jsonl format

[andrewcstewart]

Athena also supports JSON/JSONL as a file format. This option may address issue #6 (CSV column shift issue).

See Athena documentation: https://docs.aws.amazon.com/athena/latest/ug/parsing-JSON.html

Adding support for JSON format would involve the following:

• adding support for specifying different formats
• adding JSON writer logic
• adding JSON format specific Athena table definition

Example of JSON table definition:

CREATE EXTERNAL TABLE json_table (
  column_a string,
  column_b int
 )
 ROW FORMAT SERDE 'org.openx.data.jsonserde.JsonSerDe'
 WITH SERDEPROPERTIES ('ignore.malformed.json' = 'true')
 LOCATION 's3://bucket/path/';