Adds notifier for Firebase Cloud Messaging service, which delivers push notifications to mobile app users.
FCM needs authentication, credentials are supplied from Firebase web console as a json file. Path to the file is set in app properties.
As we have a single sensor in this version, we use a shared topic, called "power" and subscribe all mobile clients to this topic.
Resolves #14
Adds notifier for Firebase Cloud Messaging service, which delivers push notifications to mobile app users. FCM needs authentication, credentials are supplied from Firebase web console as a json file. Path to the file is set in app properties.
As we have a single sensor in this version, we use a shared topic, called "power" and subscribe all mobile clients to this topic.