earthobservations/wetterdienst: New cli base, fixed InfluxDB export

Change cli base to click Add support for wetterdienst core API in cli and restapi Export: Use InfluxDBClient instead of DataFrameClient and improve connection handling with InfluxDB 1.x Export: Add support for InfluxDB 2.x Fix InfluxDB export by skipping empty fields Add show() method with basic information on the wetterdienst instanc