Break out collection functions for json usage
Break out collection functions for json usage

With this change it will be possible for both type-based and
json-based result collections to use the same has_next/get_next
functions. Once the last type-based controller is converted the
Collection type can be deleted.

Change-Id: Ib1eb9a238a9ae9d42782880bd6cb6b2978d39463
Story: 1651346
Task: 10551

openstack/ironic,openstack/ironic