Use new declarative API with expression used in annotation property

Author: tomas-langer

examples/declarative/server/src/main/java/io/helidon/examples/declarative/server/ScheduledTasks.java

@@ -25,7 +25,7 @@
 class ScheduledTasks {
     private final AtomicInteger counter = new AtomicInteger(0);
 
-    @Scheduling.Cron(value = "0/5 * * * * ?", configKey = "app.scheduling.refresh-task")
+    @Scheduling.Cron(value = "${app.scheduling.refresh-task.expression:0/5 * * * * ?}")
     void refreshTask() {
         counter.incrementAndGet();
     }