Implement updateMetric and getLoad methods of ControlPlaneMonitor

- Add rrd4j jar, and wrap it as a bundle for karaf
- Implement updateMetric and getLoad methods
- Add unit test for two methods
- Revise the DefaultMetricDatabase to make it generate unique in
  memory storage space
- Revise the ControlPlaneMonitor interface
- Rename percentage to ratio, due to long string unsupport
  issue in RRD

Change-Id: Ia9d56f8e4f4bcd7ef7a29732668caa9c6a885ecf
diff --git a/apps/cpman/app/src/main/resources/definitions/MemoryMetricsPost.json b/apps/cpman/app/src/main/resources/definitions/MemoryMetricsPost.json
index ab815da..229df64 100644
--- a/apps/cpman/app/src/main/resources/definitions/MemoryMetricsPost.json
+++ b/apps/cpman/app/src/main/resources/definitions/MemoryMetricsPost.json
@@ -1,18 +1,18 @@
 {
   "type": "object",
   "required": [
-    "memoryUsedPercentage",
-    "memoryFreePercentage",
+    "memoryUsedRatio",
+    "memoryFreeRatio",
     "memoryUsed",
     "memoryFree"
   ],
   "properties": {
-    "memoryUsedPercentage": {
+    "memoryUsedRatio": {
       "type": "integer",
       "format": "int64",
       "example": "30"
     },
-    "memoryFreePercentage": {
+    "memoryFreeRatio": {
       "type": "integer",
       "format": "int64",
       "example": "70"