[VOL-4055][ONOS-8138] Adding annotations to meter to allow passing of associated information

This patch allows for adding key value elements in the meter request and in the meter generated from it.
An example is:
Annotations annotations = DefaultAnnotations.builder().set("MeterForDeviceType", "olt").build();
DefaultMeterRequest.builder().withAnnotations(annotations)
Generates:
 DefaultMeter{device=of:00000a0a0a0a0a0b, cellId=2, appId=org.opencord.olt, unit=KB_PER_SEC, isBurst=true, state=ADDED, bands=[DefaultBand{rate=100000, burst-size=5000, type=DROP, drop-precedence=null}, DefaultBand{rate=100000, burst-size=5000, type=DROP, drop-precedence=null}, DefaultBand{rate=100000, burst-size=0, type=DROP, drop-precedence=null}], annotations={MeterForDeviceType=olt}}

Change-Id: Ifaded96ebeb7956bc60cdf311180c984c3ba954e
diff --git a/core/net/src/main/java/org/onosproject/net/meter/impl/MeterManager.java b/core/net/src/main/java/org/onosproject/net/meter/impl/MeterManager.java
index 1979c61..6e0c2e7 100644
--- a/core/net/src/main/java/org/onosproject/net/meter/impl/MeterManager.java
+++ b/core/net/src/main/java/org/onosproject/net/meter/impl/MeterManager.java
@@ -242,6 +242,9 @@
         if (request.isBurst()) {
             mBuilder.burst();
         }
+        if (request.annotations() != null && !request.annotations().keys().isEmpty()) {
+            mBuilder.withAnnotations(request.annotations());
+        }
         DefaultMeter m = (DefaultMeter) mBuilder.build();
         m.setState(MeterState.PENDING_ADD);
         store.storeMeter(m).whenComplete((result, error) ->