Add FCM changes

-    public void undeploy() {
 
-    }
+    private void sendWakeUpCall(String accessToken, String registrationId) throws IOException,

-    }
+    private void sendWakeUpCall(String accessToken, String registrationId) throws IOException,
+            PushNotificationExecutionFailedException {
+        OutputStream os = null;

+        HttpURLConnection conn = null;
+
+        String fcmServerEndpoint = FCMUtil.getInstance().getContextMetadataProperties().getProperty(FCM_ENDPOINT_KEY);
+        if(fcmServerEndpoint == null) {

-            data.addProperty("data", message);
-            fcmRequest.add("data", data);
-        }
+    private static String getFCMRequest(String registrationId) {

+                        fromStream(Files.newInputStream(serviceAccountPath)).
+                        createScoped(FCM_SCOPES);
+            } catch (IOException e) {
+                log.error("Fail to initialize default OAuth application for FCM communication");

+        }
+    }
+
+    private void initContextConfigs() {

+        contextMetadataProperties = properties;
+    }
+
+    public static FCMUtil getInstance() {

+            <dependency>
+                <groupId>org.wso2.orbit.com.google.auth-library-oauth2-http</groupId>
+                <artifactId>google-auth-library-oauth2-http</artifactId>
+                <version>1.20.0.wso2v1</version>

+            <dependency>
+                <groupId>com.google.auth</groupId>
+                <artifactId>google-auth-library-oauth2-http</artifactId>
+                <version>1.20.0</version>