1.Add Webhook Tester to the test environment.
2.Create a new project and enable webhook.
3.Trigger different event types(Artifact pushed、Artifact
pulled、Artifact deleted、Scanning finished、Scanning stopped、Tag
retention finished、Replication finished、Quota near threshold、Quota exceed).
4.Verify that the message is correct in the Webhook Tester.
5.Moved Webhook CRUD test cases from Common.robot to Webhook.robot for
triage.
Signed-off-by: Yang Jiao <jiaoya@vmware.com>
