HPCC-9224 WsEcl support for starting workunits asynchronously

Asynchrounous workunits can now be created by changing the URL used to
submit queries.  Supported by HTTP-GET, SOAP, JSON, and FORM-POST.

Replacing "submit" in the url with "async" will cause workunit based
queries to immediately return the WUID of the result workunit rather
than waiting for the workunit to complete.

Synchronous URL:

http://ip:port/WsEcl/submit/query/hthor/myquery?parm1=abc

Aysnchrounous URL:

http://ip:port/WsEcl/async/query/hthor/myquery?parm1=abc

Signed-off-by: Anthony Fishbeck <Anthony.Fishbeck@lexisnexis.com>