javadoc and testclasses for backend

removed list of answers from QuizResultDTO and added quizResultId til QuestionAnswerDTO to have same correlation as Quiz has to question

FullstackProsjekt/src/backend/main/java/edu/ntnu/idatt2105/configuration/CorsConfig.java

@@ -4,13 +4,22 @@ import org.springframework.context.annotation.Configuration;
 import org.springframework.web.servlet.config.annotation.CorsRegistry;
 import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
 
+/**
+ * Configuration class for CORS (Cross-Origin Resource Sharing).
+ */
 @Configuration
 public class CorsConfig implements WebMvcConfigurer {
+
+  /**
+   * Adds CORS mapping configuration.
+   *
+   * @param registry CorsRegistry instance to configure CORS mappings.
+   */
   @Override
   public void addCorsMappings(CorsRegistry registry) {
     registry.addMapping("/**")
-        .allowedOrigins("http://localhost:5173")
-        .allowedMethods("GET", "POST", "PUT", "DELETE")
-        .allowedHeaders("*");
+            .allowedOrigins("http://localhost:5173")
+            .allowedMethods("GET", "POST", "PUT", "DELETE")
+            .allowedHeaders("*");
   }
 }