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.
Watch faces can now be selected at buid time. It's implemented in a similar way than the selection of user apps, using a list of watch face description that is generated at build time (consteval, constexpr)
When the screen switches, the full screen needs to be refreshed for the
hardware scrolling to work. This was enforced with backgroundLabels, but
is simpler to do with a rounder function.
