Move integration tests to dedicated module

This commit moves the dependency management and test source files
related to integration tests to a dedicated module.
This allows us to focus the root project on building the Spring
Framework.

See gh-23282

integration-tests/src/test/java/com/foo/Component.java

@@ -0,0 +1,42 @@
+/*
+ * Copyright 2002-2016 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.foo;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class Component {
+	private String name;
+	private List<Component> components = new ArrayList<>();
+
+	// mmm, there is no setter method for the 'components'
+	public void addComponent(Component component) {
+		this.components.add(component);
+	}
+
+	public List<Component> getComponents() {
+		return components;
+	}
+
+	public String getName() {
+		return name;
+	}
+
+	public void setName(String name) {
+		this.name = name;
+	}
+}