Add ability to remove preferences for experiment workflow
It should be possible to remove an individual preference (with confirmation) from the management panel experiment preferences overview. This can be used as a workaround to exclude a person from a specific project.
It should also be possible to remove the preference for an individual student in the overview that displays the generated matching (if student is matched, they will have a preference). (NOTE: TNW matching algorithm has its own overview page before accepting the matching).