Improve navigation by only displaying relevant coures on the front page.

Perhaps some settings/onboarding panel where students can specify which department's courses they're interested in. For example I might say I'm interested in videos from "Computer Science", "Math", "DRES", and "Statistics" which can set up the homepage default filters.

Later on this could use some type of [automatic import](https://github.com/classtranscribe/WebAPI/issues/192) as well that could set up these filters better.