Add REST API for invoking workflow.

Currently, there is no way to invoking using REST API.
I've added REST API.

json data example:

{
  "op": "workflow.invoke",
  "params": {
    "workplace": "Nova-000",
    "id": "of-overlay.workflow-nova",
    "data": {
      "mgmtIp": "192.168.10.8",
      "ovsdbPort": 6641,
      "sshAccessInfo": {
        "remoteIp": "192.168.10.8",
        "port": 22,
        "user": "root",
        "password": "iloveyou",
        "keyfile": "~/.ssh/id_rsa"
      },
      "ovsDatapathType": "system",
      "physicalPorts": [
        "nova0_1"
      ],
      "vtepIp": "120.0.0.200/24",
      "annotations": {
        "rackId": 1,
        "rackPosition": 3
      }
    }
  }
}

Change-Id: I2ce3bc5a59ce1cbe91c8c6f83bd1f25e81933ce3
diff --git a/apps/workflow/app/src/main/java/org/onosproject/workflow/impl/WorkflowNetConfigListener.java b/apps/workflow/app/src/main/java/org/onosproject/workflow/impl/WorkflowNetConfigListener.java
index bb7f875..86eccfa 100644
--- a/apps/workflow/app/src/main/java/org/onosproject/workflow/impl/WorkflowNetConfigListener.java
+++ b/apps/workflow/app/src/main/java/org/onosproject/workflow/impl/WorkflowNetConfigListener.java
@@ -44,6 +44,11 @@
     public static final String EXECUTOR_GROUPNAME = "onos/workflow-netcfg";
     public static final String EXECUTOR_PATTERN = "netcfg-event-handler";
 
+    public static final String WORKPLACE_CREATE = "workplace.create";
+    public static final String WORKPLACE_REMOVE = "workplace.remove";
+    public static final String WORKFLOW_INVOKE = "workflow.invoke";
+    public static final String WORKFLOW_TERMINATE = " workflow.terminate";
+
     private final ConfigFactory<ApplicationId, WorkflowNetConfig> configFactory =
             new ConfigFactory<ApplicationId, WorkflowNetConfig>(
                     SubjectFactories.APP_SUBJECT_FACTORY, WorkflowNetConfig.class, CONFIG_KEY) {
@@ -128,13 +133,13 @@
 
     private static Map<String, RpcCall> rpcMap = new HashMap<>();
     static {
-        rpcMap.put("workplace.create",
+        rpcMap.put(WORKPLACE_CREATE,
                 (service, desc) -> service.createWorkplace(DefaultWorkplaceDescription.valueOf(desc.params())));
-        rpcMap.put("workplace.remove",
+        rpcMap.put(WORKPLACE_REMOVE,
                 (service, desc) -> service.removeWorkplace(DefaultWorkplaceDescription.valueOf(desc.params())));
-        rpcMap.put("workflow.invoke",
+        rpcMap.put(WORKFLOW_INVOKE,
                 (service, desc) -> service.invokeWorkflow(desc.params()));
-        rpcMap.put("workflow.terminate",
+        rpcMap.put(WORKFLOW_TERMINATE,
                 (service, desc) -> service.terminateWorkflow(DefaultWorkflowDescription.valueOf(desc.params())));
     }
 }