Add graduate courses list

[iremurhan]

There is a page dedicated to the "courses", however, it only contains undergraduate courses. (If I did not miss something). Titles and course descriptions should be added.

Unfortunately, I do not know whom to assign this task to nor do I have the authorization.

Course information in general can be extracted from the old website and former syllabuses from registration or course instructors can be added too for a more detailed representation of the courses.

[doganulus]

Added to the backlog. We will come to graduate courses in later iterations.