[blazar] Extending the payload of a notification, to send the entire lease data

Hello Blazar Team, May I have the following change reviewed, for extending the payload of a notification, to send the entire lease data: *https://review.opendev.org/c/openstack/blazar/+/965448 <https://review.opendev.org/c/openstack/blazar/+/965448>* Looking for your feedback as soon as possible. Best regards. -- NITIN GUPTA