feat: display teamers' average ratings in several locations

src/Entity/Teamer.php

@@ -496,6 +496,23 @@ class Teamer implements TimestampableEntityInterface
         return $this;
     }
 
+    public function getAverageRating(): ?int
+    {
+        $feedbackCount = $this->getFeedback()->count();
+
+        if (0 === $feedbackCount) {
+            return null;
+        }
+
+        $sum = 0;
+
+        foreach ($this->getFeedback() as $feedback) {
+            $sum += $feedback->getAverageRating();
+        }
+
+        return $sum / $feedbackCount;
+    }
+
     /**
      * @return Collection<int, TrainingAttendance>
      */