Refactor: move telemetry config from componentCfg to configs.xml

1. Support to export the metrics to multiple targets
2. Add a set of properties to kafka config (key, topic, etc.)
3. Add distributedStore to manage telemetry configs
4. Add CLI to query stored telemetry configs
5. Add a set of telemetry loaders to import xml definitions
6. Add unit tests for telemetry cfg, xml cfg loader and dist store
7. Add missing javadoc for a set of implementation classes

Change-Id: I39480c9a6ac07357184d2e1094b9c9f4d36fd8b1
diff --git a/apps/openstacktelemetry/api/src/main/java/org/onosproject/openstacktelemetry/api/TelemetryConfigStore.java b/apps/openstacktelemetry/api/src/main/java/org/onosproject/openstacktelemetry/api/TelemetryConfigStore.java
new file mode 100644
index 0000000..42148f6
--- /dev/null
+++ b/apps/openstacktelemetry/api/src/main/java/org/onosproject/openstacktelemetry/api/TelemetryConfigStore.java
@@ -0,0 +1,79 @@
+/*
+ * 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.openstacktelemetry.api;
+
+import org.onosproject.openstacktelemetry.api.config.TelemetryConfig;
+import org.onosproject.openstacktelemetry.api.config.TelemetryConfig.ConfigType;
+import org.onosproject.store.Store;
+
+import java.util.Set;
+
+/**
+ * Manages inventory of telemetry config; not intended for direct use.
+ */
+public interface TelemetryConfigStore
+        extends Store<TelemetryConfigEvent, TelemetryConfigStoreDelegate> {
+
+    /**
+     * Creates a new telemetry config.
+     *
+     * @param config a telemetry config
+     */
+    void createTelemetryConfig(TelemetryConfig config);
+
+    /**
+     * Updates the existing telemetry config.
+     *
+     * @param config the existing telemetry config
+     */
+    void updateTelemetryConfig(TelemetryConfig config);
+
+    /**
+     * Removes the existing telemetry config.
+     *
+     * @param name telemetry config name
+     * @return the removed telemetry config
+     */
+    TelemetryConfig removeTelemetryConfig(String name);
+
+    /**
+     * Obtains the existing telemetry config.
+     *
+     * @param name telemetry config name
+     * @return queried telemetry config
+     */
+    TelemetryConfig telemetryConfig(String name);
+
+    /**
+     * Obtains a collection of all of telemetry configs.
+     *
+     * @return a collection of all of telemetry configs
+     */
+    Set<TelemetryConfig> telemetryConfigs();
+
+    /**
+     * Obtains a collection of telemetry configs by config type.
+     *
+     * @param type config type
+     * @return a collection of telemetry configs by config type
+     */
+    Set<TelemetryConfig> telemetryConfigsByType(ConfigType type);
+
+    /**
+     * Removes all telemetry configs.
+     */
+    void clear();
+}