Add Card and CollapsableCard and use it consistently

src/pages/courses.tsx

src/pages/index.tsx

src/pages/internal/changelog.tsx

src/pages/internal/import.tsx

src/pages/internal/jobs.tsx

src/pages/internal/sorter_files.tsx

src/pages/internal/timetable.tsx

src/styles/globals.scss

src/videoag/course/CourseListing.tsx

src/videoag/course/Medium.tsx

src/videoag/course/Player.tsx

src/videoag/job/Job.tsx

src/videoag/miscellaneous/Card.tsx

src/videoag/miscellaneous/index.ts

src/videoag/object_management/OMConfigComponent.tsx