* updates Django to 4.x and other packages (if possible) to latest versions
* Attention: Requires postgresql >= 12.0
* updates code fragments to match requirements of newer package versions
* 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
