CORD-349 Support VLAN cross-connect traffic

Change related to this topic:
- Support VLAN cross-connect traffic
    Utilize ports subjectClass to achieve. For non-xConnect port, set interface VLAN to -1
- Remove VLAN checking since we have multiple VLANs per port
- Hash the L2 interface group key generation to include VLAN as well
- Update the network-cfg.json sample

Other refactoring changes:
- Read next objective stores from srManager directly
- Use constant for flow priority
- CORD-267 Javadoc fix

Change-Id: I4ca8c2d9c8b3633a4a0101c5070d19343f7e5b90
diff --git a/src/main/java/org/onosproject/segmentrouting/grouphandler/SubnetNextObjectiveStoreKey.java b/src/main/java/org/onosproject/segmentrouting/grouphandler/SubnetNextObjectiveStoreKey.java
index d6b16c7..8e5c3ce 100644
--- a/src/main/java/org/onosproject/segmentrouting/grouphandler/SubnetNextObjectiveStoreKey.java
+++ b/src/main/java/org/onosproject/segmentrouting/grouphandler/SubnetNextObjectiveStoreKey.java
@@ -22,12 +22,18 @@
 import java.util.Objects;
 
 /**
- * Class definition of Key for Subnet to NextObjective store.
+ * Key of Subnet to NextObjective store.
  */
 public class SubnetNextObjectiveStoreKey {
     private final DeviceId deviceId;
     private final IpPrefix prefix;
 
+    /**
+     * Constructs the key of subnet next objective store.
+     *
+     * @param deviceId device ID
+     * @param prefix subnet information
+     */
     public SubnetNextObjectiveStoreKey(DeviceId deviceId,
                                        IpPrefix prefix) {
         this.deviceId = deviceId;