OZG-532 refactor: use event to finish command

...service/src/main/java/de/itvsh/ozg/mail/EMailService.java

...ervice/src/main/java/de/itvsh/ozg/mail/MailSentEvent.java

...ice/src/test/java/de/itvsh/ozg/mail/EMailServiceTest.java

pluto-server/pom.xml

...ver/src/main/java/de/itvsh/ozg/pluto/command/Command.java

...java/de/itvsh/ozg/pluto/command/CommandEventListener.java

...java/de/itvsh/ozg/pluto/command/CommandExecutedEvent.java

...in/java/de/itvsh/ozg/pluto/command/CommandRepository.java

.../main/java/de/itvsh/ozg/pluto/command/CommandService.java

...java/de/itvsh/ozg/pluto/command/CreateCommandRequest.java

...vsh/ozg/pluto/command/GrpcCreateCommandRequestMapper.java

...h/ozg/pluto/command/status/GrpcVorgangCommandService.java

...n/java/de/itvsh/ozg/pluto/command/status/StatusOrder.java

...n/java/de/itvsh/ozg/pluto/vorgang/StatusChangedEvent.java

.../main/java/de/itvsh/ozg/pluto/vorgang/VorgangService.java

.../de/itvsh/ozg/pluto/vorgang/redirect/RedirectRequest.java

...vsh/ozg/pluto/vorgang/redirect/RedirectRequestMapper.java

.../de/itvsh/ozg/pluto/command/CommandEventListenerTest.java

...sh/ozg/pluto/command/CommandExecutedEventTestFactory.java

...t/java/de/itvsh/ozg/pluto/command/CommandTestFactory.java