Replace jsonpath_ng by jsonpath_ng.ext to parse complex expressions based on filtered selections

This enhances the jsonpath output format in osmclient commands, allowing
the use of extended expressions based on selectors such as
'{.status.conditions[?(@.type=="Synced")].status}'.

Change-Id: Ic40f93e3e8e9a75b7685a81f4975a4cbe43e154b
Signed-off-by: garciadeblas <gerardo.garciadeblas@telefonica.com>