Switch to OpenWeatherMap (OWM) as weather data provider

[casasfernando]

At the moment the indicator is using any available provider (mainly US weather office -IWIN-). Unfortunately this may be less reliable for locations outside the US (especially not major cities). Switching to OWM may improve things on this aspect and libgweather already supports OWM as a provider but OWM requires an API key for the application to use their API.

At the moment I couldn't find a way to pass the OWM API key value for libgweather to use it and this is blocking the progress to implement this. I opened an issue/question but it remains unanswered.

If anyone has the answer or can point me in the right direction to pass the OWM API key to libgweather please feel free to share.

Thanks.