Improve filtering and add sorting at the course view

[ankith26]

There are some more filtering features that could be integrated

• Filter by course category
• Filter by number of reviews (would be useful to filter out courses without reviews while viewing)
• Filter courses that have the viewers review maybe?

Some useful sorting metrics

• Sort by sem and name (current behaviour)
• Sort by review count
• Sort by time of latest review comment
• Sort by average rating

[ankith26]

The sortability features have been implemented, however there are still a few minor things to be fixed

• when changing sort parameters, the review boxes don't auto-collapse as they should
• A mutation (review post, edit or delete) should trigger a metadata refresh, so that the sorting can update correctly after a mutation