Add extra items info to hosts json model

Linked items are by default returned as a list of ICS id.
When recursive is True, a list of {ics_id, serial_number, stack_member}
is returned instead.

Items are always returned sorted by stack_member or ics_id when
stack_member is null.

Allow to add the serial_number and stack_member to the Ansible variables
in csentry dynamic inventory. Useful for switches.

JIRA INFRA-1111 #action In Progress