Weather notifications

Closes https://github.com/DroidPlanner/droidplanner/issues/846

Changes:
- Show Status Bar and TTS notifications on high or extreme wind speed and solar radiation
- Wind speed is high at speed >= 5 m/s && < 10 m/s, extreme at >= 10 m/s
- Solar radiation is high at kIndex == 4, extreme at >4

TODO:
- [ ] Check whether copter has GPS fix as wind data is location-dependent?