[Weather]

### Description
The forecasts of OpenWeatherMap's API include information regarding precipitation (probability of rain, e.g.).
Please extend the the weather-plugin's data model (Weather object) to support precipitation. This would be awesome!
Official introduction can be read here:
https://openweathermap.medium.com/probability-of-precipitation-in-openweather-forecasts-f746db1e8c1

### Additional information
Examples taken from: https://openweathermap.org/forecast5
XML:

forecast.precipitation
forecast.precipitation.value Precipitation volume for the last 3 hours, mm
forecast.precipitation.unit Period of measurements. Possilbe value is 1 hour, 3 hours.
forecast.precipitation.type Type of precipitation. Possible value is rain, snow.