HPCC-10673 ECL support for reading JSON Files

Signed-off-by: Anthony Fishbeck <anthony.fishbeck@lexisnexis.com>
wHPCC-10673 Update based on review

Signed-off-by: Anthony Fishbeck <anthony.fishbeck@lexisnexis.com>
Merge pull request #6428 from afishbeck/jsonFileRead2

HPCC-10673 ECL support for reading JSON Files

Reviewed-by: Gavin Halliday <ghalliday@hpccsystems.com>