* adds needed migrations
* refactors forms.py (700+ lines) in main konova app
* splits into forms/ and forms/modals and single class/topic-files for better maintainability and overview
* fixes bug in main konova app migration which could occur if a certain compensation migration did not run before
* adds mail sending logic for new notification setting
* adds new templates for user and team based sending
* enhances all email template layout
* adds translations
* adds template message to indicate a finished-deadline is mandatory
* adds finished deadline existance to quality check of compensation-like entries
* adds proper warning to quality check result
* extends tests