HPCC-11601 Add --exception-level option to ecl-run

Sets the minimum exception severity for reporting exceptions.

Possible values "info", "warning", "error".  "info" is default and will
return all exceptions.

Signed-off-by: Anthony Fishbeck <anthony.fishbeck@lexisnexis.com>
Merge pull request #6016 from afishbeck/eclcmdIgnoreWarnings

HPCC-11601 Add --exception-level option to ecl-run

Reviewed-by: Gavin Halliday <ghalliday@hpccsystems.com>