Added Samples and Documentation for metrics

Updated documentation and sample

Updated the test to use original metrics definition

spring-cloud-task-samples/pom.xml

@@ -28,6 +28,7 @@
 		<module>task-events</module>
 		<module>batch-events</module>
 		<module>jpa-sample</module>
+		<module>task-metrics</module>
 		<module>multiple-datasources</module>
 		<module>single-step-batch-job</module>
 	</modules>