Quality management additional notification to inform teachers before a survey is launched

The aim of these new feature is to inform teacher/trainer before a planed survey is launched, with an email which is sent x days before the effective survey is ready to be filled out. We distinguish therefore two reminder texts according the different situations:

1. Announcements that students will fill out a specific survey in x days (according to the value set within the data generator)
2. Announcements via email, that a teacher/trainer shall fill out the survey reflecting how the class is performing within the teaching process

Within the the email text we give as much as possible context information reflecting the two different feedback objects.

Within the existing data generator one can configure the number of days that will launch the notification before the survey is open. This change only affects generators of type "Lectures of a coach in a course" and "Lectures of a coach in a course (follow-up survey)".