HPCC-11381 - add a sort/sortReverse methods to StringArray

Signed-off-by: Jake Smith <jake.smith@lexisnexis.com>
Merge pull request #5832 from jakesmith/hpcc-11381

HPCC-11381 - add a sort/sortReverse methods to StringArray

Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>