Add quarkus livecycle bean for frontend

dmnverifierfrontend/src/main/java/de/unikoblenz/fgbks/dmn/frontend/AppLifecycleBean.java

+package de.unikoblenz.fgbks.dmn.frontend;
+
+import io.quarkus.runtime.ShutdownEvent;
+import io.quarkus.runtime.StartupEvent;
+import javax.enterprise.context.ApplicationScoped;
+import javax.enterprise.event.Observes;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+@ApplicationScoped
+public class AppLifecycleBean {
+
+  private static final Logger LOGGER = LoggerFactory.getLogger("AppLifecycle");
+
+  void onStart(@Observes StartupEvent ev) {
+    LOGGER.info("The dmn verification application (frontend) is starting...");
+  }
+
+  void onStop(@Observes ShutdownEvent ev) {
+    LOGGER.info("The dmn verification application (frontend) is stopping...");
+  }
+}