Add application metrics in the onboarding backend

A new endpoint was introduced /onboarding-api/v1.0/actuator/prometheus
in the onboarding backend, that returns application metrics in a format
consumable by prometheus, using the micrometer library.

Change-Id: I684b5cab55947c6bedee1b838343676489ad3ebf
Issue-ID: SDC-3956
Signed-off-by: andre.schmid <andre.schmid@est.tech>
diff --git a/pom.xml b/pom.xml
index 6b1ddd4..911f9b2 100644
--- a/pom.xml
+++ b/pom.xml
@@ -191,6 +191,8 @@
         <docker.username>docker</docker.username>
         <docker.registry>nexus3.onap.org:10001</docker.registry>
 
+        <micrometer.version>1.8.4</micrometer.version>
+
         <verbose>false</verbose>
     </properties>