ONOS-4919: Implement RESTCONF client

Adding code to support RESTCONF protocol as one of
the supported SBI protocols of ONOS. This RESTCONF SBI extends
the current REST SBI protocl and adds some new APIs/functinalities
so that a provider can subscribe/register to an external restconf
server to receive notification stream.

Change-Id: I21bf0d0f0394cf788e066d743b3ade04735fe07e
diff --git a/protocols/restconf/client/api/pom.xml b/protocols/restconf/client/api/pom.xml
new file mode 100644
index 0000000..5925337
--- /dev/null
+++ b/protocols/restconf/client/api/pom.xml
@@ -0,0 +1,38 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+  ~ Copyright 2016-present Open Networking Laboratory
+  ~
+  ~ 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.
+  -->
+
+<project xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd" xmlns="http://maven.apache.org/POM/4.0.0"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
+  <modelVersion>4.0.0</modelVersion>
+  <parent>
+    <groupId>org.onosproject</groupId>
+    <artifactId>onos-restconf-client</artifactId>
+    <version>1.8.0-SNAPSHOT</version>
+    <relativePath>../pom.xml</relativePath>
+  </parent>
+  <artifactId>onos-restconf-client-api</artifactId>
+  <packaging>bundle</packaging>
+  <description>ONOS RESTCONF southbound plugin API</description>
+  <dependencies>
+      <dependency>
+          <groupId>org.onosproject</groupId>
+          <artifactId>onos-restsb-api</artifactId>
+          <version>${project.version}</version>
+          <type>bundle</type>
+      </dependency>
+  </dependencies>
+</project>