Fix chill index formula as suggested by @facko79.
Chill index is computed only for temperatures less then 10°C (50°F). Otherwise real temperature is returned.
- A new constant `WIND_AZIMUT` is added to allow creating a wind direction sensor that returns a text value from `UnitOfDir` instead of just a numeric degree value.
- The wind direction sensor entity now optionally creates both a numeric wind direction sensor using `WIND_DIR` and a text-based azimuth sensor using `WIND_AZIMUT`. If the numeric one is enabled, the text one will also be added.
So in summary, these changes improve the usability of wind data by adding a more human-readable text version alongside the existing numeric version.
schizza