Implement kubevirt router store, manager and codec with unit tests

Change-Id: Ib93a71326aa35b4817f0e6b6c97d5f57b26fe470
diff --git a/apps/kubevirt-networking/api/src/main/java/org/onosproject/kubevirtnetworking/api/AbstractWatcher.java b/apps/kubevirt-networking/api/src/main/java/org/onosproject/kubevirtnetworking/api/AbstractWatcher.java
new file mode 100644
index 0000000..f7fcfc1
--- /dev/null
+++ b/apps/kubevirt-networking/api/src/main/java/org/onosproject/kubevirtnetworking/api/AbstractWatcher.java
@@ -0,0 +1,47 @@
+/*
+ * Copyright 2021-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.kubevirtnetworking.api;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import org.onlab.osgi.DefaultServiceDirectory;
+import org.onlab.osgi.ServiceDirectory;
+import org.onosproject.codec.CodecContext;
+import org.onosproject.codec.CodecService;
+import org.onosproject.codec.JsonCodec;
+
+/**
+ * Abstract watcher.
+ */
+public class AbstractWatcher implements CodecContext {
+
+    private static ServiceDirectory services = new DefaultServiceDirectory();
+    private final ObjectMapper mapper = new ObjectMapper();
+
+    @Override
+    public ObjectMapper mapper() {
+        return mapper;
+    }
+
+    @Override
+    public <T> JsonCodec<T> codec(Class<T> entityClass) {
+        return services.get(CodecService.class).getCodec(entityClass);
+    }
+
+    @Override
+    public <T> T getService(Class<T> serviceClass) {
+        return services.get(serviceClass);
+    }
+}