When in a course, history does not limit to that course

What does this MR do?

Filter the requests when "../history/course/XX/student/YY" is visited, such that only the requests to the corresponding course are shown.

Screenshots

The only course that should be shown is Algorithms and Datastructures

Before

After

Does this MR meet the acceptance criteria?

• does not limit history to that actual course XX
• shows history of student ZZ even if ZZ is not in course XX (aka: privacy leaks)

Closes #184 (closed)