SimpleWeather service : new weather implementation

This new implementation of the weather feature provides a new BLE API and a new weather service.
The API uses a single characteristic that allows companion apps to write the weather conditions (current and forecast for the next 5 days).
The SimpleWeather service exposes those data as std::optional fields.

This new implementation replaces the previous WeahterService.

The API is documented in docs/SimpleWeatherService.md.

src/displayapp/Controllers.h

@@ -20,7 +20,7 @@ namespace Pinetime {
     class MotionController;
     class AlarmController;
     class BrightnessController;
-    class WeatherService;
+    class SimpleWeatherService;
     class FS;
     class Timer;
     class MusicService;
@@ -43,7 +43,7 @@ namespace Pinetime {
       Pinetime::Controllers::MotionController& motionController;
       Pinetime::Controllers::AlarmController& alarmController;
       Pinetime::Controllers::BrightnessController& brightnessController;
-      Pinetime::Controllers::WeatherService* weatherController;
+      Pinetime::Controllers::SimpleWeatherService* weatherController;
       Pinetime::Controllers::FS& filesystem;
       Pinetime::Controllers::Timer& timer;
       Pinetime::System::SystemTask* systemTask;