[CORD-458] Updates ARP handler

Changes:
- SR application uses NRM;
- Adds hooks for ND protocol;
- Updates ARP handler to better leverage on NRM;
- Reworks to take into account IPv4/IPv6 together;

Change-Id: Iab55b8c5ef7d973928d8ad47e2c2a482fb9c5c8a
diff --git a/src/main/java/org/onosproject/segmentrouting/config/DeviceProperties.java b/src/main/java/org/onosproject/segmentrouting/config/DeviceProperties.java
index 565dbe1..e4e71db 100644
--- a/src/main/java/org/onosproject/segmentrouting/config/DeviceProperties.java
+++ b/src/main/java/org/onosproject/segmentrouting/config/DeviceProperties.java
@@ -15,8 +15,8 @@
  */
 package org.onosproject.segmentrouting.config;
 
-import org.onlab.packet.Ip4Prefix;
 import org.onlab.packet.IpAddress;
+import org.onlab.packet.IpPrefix;
 import org.onlab.packet.MacAddress;
 import org.onosproject.net.DeviceId;
 import org.onosproject.net.PortNumber;
@@ -111,6 +111,6 @@
      * @throws DeviceConfigNotFoundException if the device configuration is not found
      * @return a map that contains all subnet-to-ports mapping of given device
      */
-    Map<Ip4Prefix, List<PortNumber>> getSubnetPortsMap(DeviceId deviceId)
+    Map<IpPrefix, List<PortNumber>> getSubnetPortsMap(DeviceId deviceId)
             throws DeviceConfigNotFoundException;
 }