HPCC-9034 Use Ajax call and structure array for deleting

Multiple package maps may be deleted in one service request.
The information about one package map contains multiple
items. Structure array is the best option to pass the
information. To pass it in a service request, XML data is
sent through Dojo Ajax function. The response has to be
parsed since it is in a special SOAP/XML format.

Signed-off-by: Kevin Wang <kevin.wang@lexisnexis.com>