Merge branch '624-sos-events-misc' into 'develop'

src/api/serializers.py

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

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

src/backoffice/templates/backoffice/schedules_index.html

src/core/admin.py

src/plainui/jinja2/plainui/search.html.j2