JAVA-10605: Move multimodulemavenproject from core-java-modules to (#12309)

* JAVA-10605: Move multimodulemavenproject from core-java-modules to
maven-modules

* JAVA-10605: Move multimodulemavenproject to jdk9 build

maven-modules/multimodulemavenproject/entitymodule/src/main/java/com/baeldung/entitymodule/User.java

@@ -0,0 +1,19 @@
+package com.baeldung.entitymodule;
+
+public class User {
+
+    private final String name;
+
+    public User(String name) {
+        this.name = name;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    @Override
+    public String toString() {
+        return "User{" + "name=" + name + '}';
+    }
+}

maven-modules/multimodulemavenproject/entitymodule/src/main/java/module-info.java

@@ -0,0 +1,3 @@
+module com.baeldung.entitymodule {
+    exports com.baeldung.entitymodule;
+}