Made the names for travel expense classes much shorter. More package structure.
Removed useless interfaces for vacation requests.
Moved the status enum into the vacation request class.
More packages for billable times and work times.
Some test package refactoring.
Moved some scheduled jobs general files to an own package.
Forgot to close connections, made them autocloseable.
Added integration test for the uuid mapper.
Added a unit test for the MailApproveService
Added an integration test for the travel expense type endpoint.
Added some test for the travel expense report resource.
Added a test for the vacation request scheduled job