User needs to enter his data again when checkin is in "override mode"

[oliverhummel]

... which allows to check into a full when the appropriate parameter is set in application.properties. This is somewhat annoying.

I belive this might be quite easy to fix when the click on "Trotzdem Anmelden" (in rooms/full.html) does not lead to the checkin form again, but to the link that is used for auto-checkin.