Combined login and registration in the mobile menu
Combined login and registration in the mobile menu

Closes #3225

WoltLab/WCF,WoltLab/WCF,Cyperghost/WCF,Cyperghost/WCF,WoltLab/WCF,SoftCreatR/WCF,SoftCreatR/WCF,WoltLab/WCF,Cyperghost/WCF,Cyperghost/WCF,SoftCreatR/WCF,Cyperghost/WCF,SoftCreatR/WCF