Code snippets for article BAEL-818 (#1934)

* Quartz example for article: Introduction to Quartz

* Adding new module for Java Quartz

* Removing Quartz code from jee7 module

* Fixing folder structure

* Removing java-quartz module and adding code snippets in libraries module

libraries/src/main/java/com/baeldung/quartz/SimpleJob.java

@@ -0,0 +1,13 @@
+package com.baeldung.quartz;
+
+import org.quartz.Job;
+import org.quartz.JobExecutionContext;
+import org.quartz.JobExecutionException;
+
+public class SimpleJob implements Job {
+
+    public void execute(JobExecutionContext arg0) throws JobExecutionException {
+        System.out.println("This is a quartz job!");
+    }
+
+}