HPCC-11459 Add flag to toXML to allow newlines only formatting

Signed-off-by: Jake Smith <jake.smith@lexisnexis.com>
Merge pull request #5901 from jakesmith/hpcc-11459

HPCC-11459 Add flag to toXML to allow newlines only formatting

Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>