Notification Request Parameters differs from the victoria specs.

[Wataru Juso]

＃ Problem
I found that the implementation is different from the Data described in the Spec.
* https://specs.openstack.org/openstack/tacker-specs/specs/victoria/support-notification-api-based-on-etsi-nfv-sol.html

The data model described in the Spec is defined in ETSI SOL003, and the following parameters are missing.
* https://www.etsi.org/deliver/etsi_gs/NFV-SOL/001_099/003/02.06.01_60/gs_NFV-SOL003v020601p.pdf

ETSI SOL003 v2.6.1:
 5.5.3.1 Type: LccnLinks
  - vnfInstance
  - vnfLcmOpOcc
 5.5.2.12a Type: VnfInfoModifications
  - metadata

＃ Affected
There is a possibility that the receiver will not be able to view the data.

* sample: Instantiate starting notification
Body:
{
  "notificationType": "VnfLcmOperationOccurrenceNotification",
  "notificationStatus": "START",
  "operationState": "STARTING",
  "vnfInstanceId": "fad7539e-c2a5-49db-8a75-960a56b73d23",
  "operation": "INSTANTIATE",
  "isAutomaticInvocation": false,
  "vnfLcmOpOccId": "0edcad5a-61f2-4cbb-8c6e-f46226049a5d",
  "_links": {
    "subscription": {
      "href": "http://localhost:9890//vnflcm/v1/subscriptions/fb6be75b-d638-4eba-bfde-325b221be35d"
    }
  },
  "id": "e8758e1e-f02c-42a0-b222-a782a1ce3d74",
  "subscriptionId": "fb6be75b-d638-4eba-bfde-325b221be35d",
  "timeStamp": "2020-11-20T02:27:44.469251"
}

Send result:
INFO tacker.conductor.conductor_server [req-e1a9184e-7393-4a5a-bb8e-75381b2a4805 [nfv nfv_user] send success notify[{"notificationType": "VnfLcmOperationOccurrenceNotification", "notificationStatus": "START", "operationState": "STARTING", "vnfInstanceId": "fad7539e-c2a5-49db-8a75-960a56b73d23", "operation": "INSTANTIATE", "isAutomaticInvocation": false, "vnfLcmOpOccId": "0edcad5a-61f2-4cbb-8c6e-f46226049a5d", "_links": {"subscription": {"href": "http://localhost:9890//vnflcm/v1/subscriptions/fb6be75b-d638-4eba-bfde-325b221be35d"}}, "id": "e8758e1e-f02c-42a0-b222-a782a1ce3d74", "subscriptionId": "fb6be75b-d638-4eba-bfde-325b221be35d", "timeStamp": "2020-11-20T02:27:44.469251"}

# Expected behavior:
- Implement field of VnfInfoModifications class.
- Modify send_notification function.

[Wataru Juso (w-juso)]

Fix proposed to branch: master
Review: https://review.opendev.org/c/openstack/tacker/+/774213

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/tacker 5.0.0.0rc1 release candidate.