group testing modules (#2914)

* move security content from spring-security-rest-full

* swagger update

* move query language to new module

* rename spring-security-rest-full to spring-rest-full

* group persistence modules

* group testing modules

* try fix conflict

* cleanup

testing-modules/junit-5/src/main/java/com/baeldung/junit5/Greetings.java

@@ -0,0 +1,9 @@
+package com.baeldung.junit5;
+
+public class Greetings {
+
+    public static String sayHello() {
+        return "Hello";
+    }
+
+}