Merge branch 'main' into issue-465

app/controllers/my_courses.php

app/views/admin/courses/_course.php

app/views/course/timesrooms/_irregularEvents.php

app/views/course/timesrooms/_regularEvents.php

app/views/my_institutes/index.php

db/migrations/1.314_step_00349.php

db/studip.sql

db/studip_default_data.sql

db/studip_demo_data.sql

db/studip_mvv_demo_data.sql

db/studip_root_user.sql

lib/classes/Icon.class.php

lib/models/SeminarCycleDate.class.php