feat: add EvaluationResult class to encapsulate precision, recall, and F1 score

src/main/java/de/th_luebeck/ws25/EvaluationResult.java

@@ -0,0 +1,13 @@
+package de.th_luebeck.ws25;
+
+public class EvaluationResult {
+    double precision;
+    double recall;
+    double f1Score;
+
+    EvaluationResult(double precision, double recall, double f1Score) {
+        this.precision = precision;
+        this.recall = recall;
+        this.f1Score = f1Score;
+    }
+}