Änderung von Überresten von "rc3" zu "Hub"

src/backoffice/apps.py

src/backoffice/locale/de/LC_MESSAGES/django.po

src/backoffice/locale/en/LC_MESSAGES/django.po

src/backoffice/templates/backoffice/base.html

src/backoffice/views/auth.py

src/core/admin.py

src/core/locale/de/LC_MESSAGES/django.po

src/core/utils.py