NodeJS version of barbora-delivery-spot-alert with push notification support

Usage:

1. yarn
2. Put barbora.lt cookie to COOKIE variable in .env file.
3. Select your preferred delivery or pickup address in barbora.lt.
4. (Optional) To receive push notifications, set FCM server key and device token to FCM_SERVER_KEY and FCM_TOKEN variables in .env.
5. (Optional) To only get notified of times earlier than some date, set LATEST_DELIVERY_INTERVAL_IN_DAYS in .env.
6. yarn start