HPCC-9225 Allow WsEcl caller to specify jobname

By default WsEcl give a result workunit the same jobname as the publish
query workunit.  Allow jobname=<name> to be specified in the url used
to submit the query so that the user can create a unique jobname
each time the query is invoked.

Signed-off-by: Anthony Fishbeck <Anthony.Fishbeck@lexisnexis.com>