Adding topology overlay support for the server-side topo layout app.

Also:
- parametrized access network layout in preparation for multiple variants
- removed WS authentication code temporarily until proper forced-logout is implemented
- updated STC warden environment (test only)

Change-Id: I0adbe60737828db79350e7eb2fc72cf313b78a28
diff --git a/apps/layout/src/main/java/org/onosproject/layout/LayoutOverlayMessageHandler.java b/apps/layout/src/main/java/org/onosproject/layout/LayoutOverlayMessageHandler.java
new file mode 100644
index 0000000..f66f1bd
--- /dev/null
+++ b/apps/layout/src/main/java/org/onosproject/layout/LayoutOverlayMessageHandler.java
@@ -0,0 +1,74 @@
+/*
+ * Copyright 2018-present Open Networking Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onosproject.layout;
+
+import com.fasterxml.jackson.databind.node.ObjectNode;
+import com.google.common.collect.ImmutableSet;
+import org.onlab.osgi.ServiceDirectory;
+import org.onosproject.ui.RequestHandler;
+import org.onosproject.ui.UiConnection;
+import org.onosproject.ui.UiMessageHandler;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.Collection;
+
+/**
+ * ONOS UI Layout Topology-Overlay message handler.
+ */
+public class LayoutOverlayMessageHandler extends UiMessageHandler {
+
+    private final Logger log = LoggerFactory.getLogger(getClass());
+
+    private static final String DO_LAYOUT = "doLayout";
+    private static final String TYPE = "type";
+
+    RoleBasedLayoutManager layoutManager;
+
+    @Override
+    public void init(UiConnection connection, ServiceDirectory directory) {
+        super.init(connection, directory);
+        layoutManager = directory.get(RoleBasedLayoutManager.class);
+    }
+
+    @Override
+    protected Collection<RequestHandler> createRequestHandlers() {
+        return ImmutableSet.of(
+                new LayoutHandler()
+        );
+    }
+
+    private final class LayoutHandler extends RequestHandler {
+
+        public LayoutHandler() {
+            super(DO_LAYOUT);
+        }
+
+        @Override
+        public void process(ObjectNode payload) {
+            String algorithm = string(payload, TYPE);
+            switch (algorithm) {
+                case "access":
+                    layoutManager.layout(new AccessNetworkLayout());
+                    break;
+                default:
+                    layoutManager.layout(new DefaultForceLayout());
+                    break;
+            }
+        }
+    }
+
+}
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