Refactor Spring Integration metrics support

Update Spring Integration metrics support since Spring Integration
`4.3.6`+ no longer needs `spring-integration-jmx` enable
`MessageChannel`, `MessageHandler` and `MessageSource` metrics.

- Add `IntegrationManagementConfiguration` conditional auto-configuration
  to provide `@EnableIntegrationManagement` when JMX is `enabled` or there
  is no `IntegrationManagementConfigurer.MANAGEMENT_CONFIGURER_NAME` bean.
  By default this bean doesn't exist and you explicitly should declare it
  (e.g. via `@EnableIntegrationManagement`) if you would like to collect
  metrics. At the same time Spring Integration enables it when JMX
  management is present (that is a purpose of that new
  `IntegrationManagementConfiguration`)

- Change `SpringIntegrationMetricReader` to read metrics from the
  `IntegrationManagementConfigurer`, not `IntegrationMBeanExporter`

- Change `PublicMetricsAutoConfiguration` to register
  `IntegrationManagementConfigurer.MANAGEMENT_CONFIGURER_NAME` bean if
  not present. Since we are here in `actuator`, therefore we are
  interested in the metrics for SI as well.

- Since we don't need JMX for the metrics any more, remove SI-JMX
  dependency from the `spring-boot-starter-integration`.

- Remove `IntegrationManagementConfiguration` modification from the
  `integrationMbeanExporter()`, since that looks like mutation of an
  external object, when end-user would prefer their own options.
  Therefore we don't need `ObjectProvider<IntegrationManagementConfigurer>`, too

- Add missed `MessageSourceMetrics` gathering for the
  `SpringIntegrationMetricReader`

Closes gh-7722

spring-boot-actuator/src/test/java/org/springframework/boot/actuate/metrics/integration/SpringIntegrationMetricReaderNoJmxTests.java

@@ -0,0 +1,61 @@
+/*
+ * Copyright 2012-2016 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
+ *
+ *      http://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 org.springframework.boot.actuate.metrics.integration;
+
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.beans.factory.annotation.Qualifier;
+import org.springframework.boot.actuate.autoconfigure.PublicMetricsAutoConfiguration;
+import org.springframework.boot.actuate.endpoint.MetricReaderPublicMetrics;
+import org.springframework.boot.autoconfigure.integration.IntegrationAutoConfiguration;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.context.annotation.Import;
+import org.springframework.test.annotation.DirtiesContext;
+import org.springframework.test.context.junit4.SpringRunner;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Tests for {@link SpringIntegrationMetricReader}.
+ *
+ * @author Artem Bilan
+ */
+@RunWith(SpringRunner.class)
+@SpringBootTest("spring.jmx.enabled=false")
+@DirtiesContext
+public class SpringIntegrationMetricReaderNoJmxTests {
+
+	@Autowired
+	@Qualifier("springIntegrationPublicMetrics")
+	private MetricReaderPublicMetrics integrationMetricReader;
+
+	@Test
+	public void test() {
+		assertThat(this.integrationMetricReader.metrics().size() > 0).isTrue();
+	}
+
+	@Configuration
+	@Import({IntegrationAutoConfiguration.class, PublicMetricsAutoConfiguration.class})
+	protected static class TestConfiguration {
+
+	}
+
+}

spring-boot-actuator/src/test/java/org/springframework/boot/actuate/metrics/integration/SpringIntegrationMetricReaderTests.java

@@ -26,7 +26,7 @@ import org.springframework.boot.test.context.SpringBootTest;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.context.annotation.Import;
-import org.springframework.integration.monitor.IntegrationMBeanExporter;
+import org.springframework.integration.support.management.IntegrationManagementConfigurer;
 import org.springframework.test.annotation.DirtiesContext;
 import org.springframework.test.context.junit4.SpringRunner;
 
@@ -36,6 +36,7 @@ import static org.assertj.core.api.Assertions.assertThat;
  * Tests for {@link SpringIntegrationMetricReader}.
  *
  * @author Dave Syer
+ * @author Artem Bilan
  */
 @RunWith(SpringRunner.class)
 @SpringBootTest("spring.jmx.enabled=true")
@@ -55,8 +56,8 @@ public class SpringIntegrationMetricReaderTests {
 	protected static class TestConfiguration {
 
 		@Bean
-		public SpringIntegrationMetricReader reader(IntegrationMBeanExporter exporter) {
-			return new SpringIntegrationMetricReader(exporter);
+		public SpringIntegrationMetricReader reader(IntegrationManagementConfigurer managementConfigurer) {
+			return new SpringIntegrationMetricReader(managementConfigurer);
 		}
 
 	}