Give elevation points

[gabrieljaegerde]

As of now, users only get points for the distance they accompany me for. Since I go much slower uphill, it would be nice to also introduce a metric that has to do with elevation: elevation points.

Possible course of action:

1. Write a function to retrieve the elevation at a given point.
   below is a quick example. This uses the geocoder package. I did not do research into other packages and it might thus not be the optimal one.

import geocoder
def get_elevation(self, lon, lat):
    g = geocoder.elevation([lat,lon]) 
    return g.meters

**look into the order of lat,lon in geocoder (some packages to lat,lon others lon,lat)

2. Wherever we append to locations_during_song (def location(self, update, context) and def handle_location_tracking(self, chat_id)), also include the elevation at the current location like so:

current elevation = self.get_elevation(lon, lat)
self.locations_during_song.append(
                {
                    "lon": self.current_lon,
                    "lat": self.current_lat,
                    "time": datetime.now(pytz.utc).__str__(),
                    "elevation": current_elevation,
                }
            )

when the total distance is calculated (currently def calculate_distance(locations_during_song)), also calculate the total elevation that the song has accompanied me for. That function name should then probably be changed to: calculate_distance_and_elevation. Save the total elevation into the locations.json too as elevation_difference.

Note that the elevation points can also be negative if the user has accompanied me on mostly downhills :D.