Mark Wheeldon

This also allows using the cordova secure storage - https://github.com/pradeep1991singh/cordova-plugin-secure-key-store#readme

These are now throwing `Error sending to topic FirebaseMessagingError: An unknown server error was returned. Raw server response: "{"error":"Deprecated endpoint, see https://firebase.google.com/docs/cloud-messaging/migrate-v1"}"`

Thanks @DevDianDankie, I also had success using a `TopicMessage` and `.send`. Seems like an oversight to not have the old functions migrated or depicated, and we certainly got caught off...