Merge branch 'develop' into testing

.gitignore

app/Dockerfile

app/Dockerfile.prod

app/entrypoint.prod.sh

app/entrypoint.sh

app/gunicorn.conf.py

app/manage.py

app/requirements.txt

app/vkk/__init__.py

app/vkk/apps.py

app/vkk/generic/__init__.py

app/vkk/generic/forms.py

app/vkk/generic/mixins.py

app/vkk/generic/views.py

app/vkk/locale/de/LC_MESSAGES/django.mo

app/vkk/locale/de/LC_MESSAGES/django.po

app/vkk/migrations/0001_initial.py

...2_departmentcosts_departmentdate_generalcosts_and_more.py

.../0003_department_invoice_number_receipt_buper_and_more.py

app/vkk/migrations/0004_alter_receipt_buper.py