Feature/createevent

It would be good if it is merged because i got todo stuff with lisa tomorrow on this.
Features: i can create an Event, when it is created i go to an overview and i can stop the event

Things that are missing:
Tests (which ones would be appropriate here??)
Key is hardcoded
Link is not set
=> Both points are still open for discussion and must be checked with lisa for voting and thomas for architecture

Things that could improve:
showing somehwere that name is requiered (button is just disabled currently)