Merge branch 'develop' into feature/theme_switcher

src/plainui/jinja2/plainui/components/calendar.html

src/plainui/jinja2/plainui/fahrplan.html

src/plainui/jinja2/plainui/landing.html

src/plainui/jinja2/plainui/public_fahrplan.html

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

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

src/plainui/static/plainui/js/modal.js