Implement kubevirt node service, expose it through REST API and CLI

Change-Id: Ieebd2652af31344df3a7c91d3669a2ba150cb57f
diff --git a/apps/kubevirt-node/api/src/main/java/org/onosproject/kubevirtnode/api/KubevirtNodeStore.java b/apps/kubevirt-node/api/src/main/java/org/onosproject/kubevirtnode/api/KubevirtNodeStore.java
new file mode 100644
index 0000000..b6a9f03
--- /dev/null
+++ b/apps/kubevirt-node/api/src/main/java/org/onosproject/kubevirtnode/api/KubevirtNodeStore.java
@@ -0,0 +1,63 @@
+/*
+ * Copyright 2020-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.kubevirtnode.api;
+
+import org.onosproject.store.Store;
+
+import java.util.Set;
+
+/**
+ * Manages inventory of KubevirtNode; not intended for direct use.
+ */
+public interface KubevirtNodeStore extends Store<KubevirtNodeEvent, KubevirtNodeStoreDelegate> {
+
+    /**
+     * Creates a new node.
+     *
+     * @param node kubevirt node
+     */
+    void createNode(KubevirtNode node);
+
+    /**
+     * Updates the node.
+     *
+     * @param node kubevirt node
+     */
+    void updateNode(KubevirtNode node);
+
+    /**
+     * Removes the node.
+     *
+     * @param hostname kubevirt node hostname
+     * @return removed kubevirt node; null if no node mapped for the hostname
+     */
+    KubevirtNode removeNode(String hostname);
+
+    /**
+     * Returns all registered nodes.
+     *
+     * @return set of kubevirt nodes
+     */
+    Set<KubevirtNode> nodes();
+
+    /**
+     * Returns the node with the specified hostname.
+     *
+     * @param hostname hostname
+     * @return kubevirt node
+     */
+    KubevirtNode node(String hostname);
+}