Narrowcasting

There are two scenarios of narrowcasting:
1. Narrowcasting message is about some events in the past.
After submitting the narrowcasting message to the server, app side won't show notifications until a couple hours later. Need to verify if locations are logged properly. Also if there's any way to increase the background task frequency.

2. Narrowcasting message is about events in the future, when user carries the app goes to the region within the time range, app should show alert.
- [ ] Need to add notification to the notification module on homepage
- [ ] Test if the notification will show up.