IAAS-10: Add a science gateway operator to an API-enabled IaaS allocation

Executive Summary: 
A researcher needs to be able to add a science gateway operator to his/her API-enabled allocation on an IaaS host. This will allow the researcher to use the gateway as a means for using his/her allocation.
User Importance Summary: 
Researchers are increasingly using externally hosted ("cloud") virtual machines to extend their computing environments without requiring capital investment. The ability to use these resources via easy-to-use science gateway interfaces makes these resources accessible to a wider range of researchers, educators, and students.
Target Communities and Sizes: 
Allocated researchers - 1,000 < N < 10,000 Researchers - 10,000 < N < 100,000 Allocated educators - 100 < N < 1,000 Educators - 10,000 < N < 100,000