Fix certain milestones not getting activated (#54)

There was a missing bean definition that was responsible for marking certain milestones based on system events.

Fixes #53

## How to test
1. Log in as an author
2. Go to "Peer" tab within a project
3. Request a peer review
4. [If needed] Switch to another author and request another review
5. Perform a peer review
6. See that the peer reviewer completed milestone (first or second depending) is marked as completed

Reviewed-on: #54
Reviewed-by: Nico Athanassiadis <nico@dsv.su.se>
Co-authored-by: Andreas Svanberg <andreass@dsv.su.se>
Co-committed-by: Andreas Svanberg <andreass@dsv.su.se>

core/src/main/java/se/su/dsv/scipro/CoreConfig.java

@@ -96,6 +96,7 @@ import se.su.dsv.scipro.match.TargetRepository;
 import se.su.dsv.scipro.match.TargetServiceImpl;
 import se.su.dsv.scipro.milestones.MilestoneActivityTemplateRepository;
 import se.su.dsv.scipro.milestones.service.ActivateCompletedMilestonesOnNewProjects;
+import se.su.dsv.scipro.milestones.service.MilestoneActivator;
 import se.su.dsv.scipro.milestones.service.MilestoneActivityTemplateService;
 import se.su.dsv.scipro.milestones.service.impl.MilestoneActivityTemplateServiceImpl;
 import se.su.dsv.scipro.milestones.service.impl.MilestonePhaseTemplateServiceImpl;
@@ -1129,4 +1130,21 @@ public class CoreConfig {
     public GroupFacadeImpl groupFacade() {
         return new GroupFacadeImpl();
     }
+
+    @Bean
+    public MilestoneActivator milestoneActivator(
+        EventBus eventBus,
+        MilestoneServiceImpl milestoneService,
+        MilestoneActivityTemplateService milestoneActivityTemplateService,
+        FinalSeminarService finalSeminarService,
+        NotificationController notificationController
+    ) {
+        return new MilestoneActivator(
+            milestoneActivityTemplateService,
+            milestoneService,
+            eventBus,
+            finalSeminarService,
+            notificationController
+        );
+    }
 }

core/src/test/java/se/su/dsv/scipro/test/BeanDefinitionsTest.java

@@ -0,0 +1,18 @@
+package se.su.dsv.scipro.test;
+
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+
+import jakarta.inject.Inject;
+import org.junit.jupiter.api.Test;
+import se.su.dsv.scipro.milestones.service.MilestoneActivator;
+
+public class BeanDefinitionsTest extends IntegrationTest {
+
+    @Inject
+    MilestoneActivator milestoneActivator;
+
+    @Test
+    public void milestone_activator() {
+        assertNotNull(milestoneActivator);
+    }
+}