refs #4083 make it possible to set default report date in settings
refs #4083 load default report date on app start and update date once it changes. Do no longer change the report date when someone switches an account
refs #4083 set the defaultReportDate setting based on the users account setting if none is set yet
refactored visitor screen to use Alloys new dynamic styling feature
fix the platform error message is displayed instead of the human readable error message in case of a network error