CLOUDSTACK-6052: List VM enhancement to support querying with multiple VM IDs
New parameter 'ids' added to listVirtualMachine API. The syntax looks like
http://localhost:8096/api?command=listVirtualMachines&listAll=true&ids=eddac053-9b12-4d2e-acb7-233de2e98112,009966fc-4d7b-4f84-8609-254979ba0134
The new parameter will be mutually exclusive with the existing 'id' parameter.