Table of ta ratings

Closes issue #593 (closed). Adds average ratings per TA and if the number is less than 2 it is not presented. Rounds the average rating to an empty, half-filled or full star. Also presents it as a number to the side rounded to one decimal. Creates a DTO for the assistant table. Also tests.

src/main/java/nl/tudelft/queue/controller/EditionController.java

@@ -704,9 +704,7 @@ public class EditionController {
 			@RequestParam(required = false, defaultValue = "") List<Lab> labs,
 			Model model) {
 		List<LabRequest> requests = ess.getFilteredRequests(labs);
-
-		model.addAttribute("assistants", ess.countRequestsPerAssistant(requests).entrySet());
-
+		model.addAttribute("assistants", ess.ratingAndRequestsForAssistant(requests));
 		return "edition/view/status :: #assistant-table";
 	}