[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 a06a037..39ef3d9 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
@@ -262,6 +262,9 @@
         if (request.isBurst()) {
             mBuilder.burst();
         }
+        if (request.annotations() != null && !request.annotations().keys().isEmpty()) {
+            mBuilder.withAnnotations(request.annotations());
+        }
         DefaultMeter m = (DefaultMeter) mBuilder.build();
         // Meter installation logic (happy ending case)
         // PENDING -> stats -> ADDED -> future completes