[ONOS-4014] Refactor *Id classes to extend from Identifier class

- Refactor most of *Id classes in onos-api package
- Refactor all of *Id classes in incubator package

Change-Id: Ief6322d3fb42c80e82f695e9d4dcee439346215b
diff --git a/core/api/src/main/java/org/onosproject/net/intent/IntentId.java b/core/api/src/main/java/org/onosproject/net/intent/IntentId.java
index b9a30d2..4494eea 100644
--- a/core/api/src/main/java/org/onosproject/net/intent/IntentId.java
+++ b/core/api/src/main/java/org/onosproject/net/intent/IntentId.java
@@ -16,6 +16,7 @@
 package org.onosproject.net.intent;
 
 import com.google.common.annotations.Beta;
+import org.onlab.util.Identifier;
 import org.onosproject.net.newresource.ResourceConsumer;
 
 /**
@@ -23,9 +24,7 @@
  * <p>This class is immutable.</p>
  */
 @Beta
-public final class IntentId implements ResourceConsumer {
-
-    private final long value;
+public final class IntentId extends Identifier<Long> implements ResourceConsumer {
 
     /**
      * Creates an intent identifier from the specified long representation.
@@ -41,7 +40,7 @@
      * Constructor for serializer.
      */
     IntentId() {
-        this.value = 0;
+        super(0L);
     }
 
     /**
@@ -50,7 +49,7 @@
      * @param value the underlying value of this ID
      */
     IntentId(long value) {
-        this.value = value;
+        super(value);
     }
 
     /**
@@ -59,29 +58,12 @@
      * @return the value
      */
     public long fingerprint() {
-        return value;
-    }
-
-    @Override
-    public int hashCode() {
-        return Long.hashCode(value);
-    }
-
-    @Override
-    public boolean equals(Object obj) {
-        if (obj == this) {
-            return true;
-        }
-        if (!(obj instanceof IntentId)) {
-            return false;
-        }
-        IntentId that = (IntentId) obj;
-        return this.value == that.value;
+        return identifier;
     }
 
     @Override
     public String toString() {
-        return "0x" + Long.toHexString(value);
+        return "0x" + Long.toHexString(identifier);
     }
 
 }