Create notification settings more understandable and more flexible

Hello! Current notifications settings is hard for understanding and there is some limitations. For example I can’t set to get e-mails notifiacation of updates on group 1, group2, group3 and to get all updates about group4, group 5 as Zammad interface notifications… For now I can set either one or the other for all groups and I cant choose for different groups different notifications.
So, to make notification settings more flexible and more understandable I suggest to change notfication settings to something like this: