Simplify PingCreatedEvent and Add Message Payload Documentation#5

luismr merged 2 commits intomainluismr/flight-tracker-event-server-java:mainfrom

feature/ping-created-event-decoupled-from-model-to-use-ping-dtoluismr/flight-tracker-event-server-java:feature/ping-created-event-decoupled-from-model-to-use-ping-dtoCopy head branch name to clipboard