Add meteo forecast

[RCgmbh]

(probably split the issue later)

• download openweathermap data with a service when online
• download data for current location and for waypoints on the active route
• show forecast in meteo area for current locations
• show forecast for waypoints (maybe based on ETA), in meteo area or in compact form on the map
• download grib files
• offer grib layer on the map (with time slider)
• remove moon thing from sensors page, create new page with moon phase, moonrise/-set, sunrise/sunset and maybe some more geodesy/astronomy data, nicely presented