[docs] filters.clean_gps_nearby_points_by_distances radius lacking unit of measure

[JoaoCarabetta]

Describe the bug There is no unit on the radius of filters.clean_gps_nearby_points_by_distances

I suppose that it is meters, but it should be explicit.

Current docstring

Removes points from the trajectories when the distance between them and the
point before is smaller than the value set by the user.

Parameters
----------
move_data : dataframe
    The input trajectory data
label_id : str, optional
     Indicates the label of the id column in the user dataframe, by default TRAJ_ID
radius_area : float, optional
    Species the minimum distance a point must have to it"srs previous point
    in order not to be dropped, by default 10
label_dtype : type, optional
    Represents column id type, ,y default np.float64.
inplace : boolean, optional
    if set to true the operation is done in place, the original
    dataframe will be altered and None is returned, be default False

Proposed Docstring

Removes points from the trajectories when the distance in meters between them and the
point before is smaller than the value set by the user.

Parameters
----------
move_data : dataframe
    The input trajectory data
label_id : str, optional
     Indicates the label of the id column in the user dataframe, by default TRAJ_ID
radius_area : float, optional
    Species the minimum distance in meters a point must have to it's previous point
    in order not to be dropped, by default 10
label_dtype : type, optional
    Represents column id type, ,y default np.float64.
inplace : boolean, optional
    if set to true the operation is done in place, the original
    dataframe will be altered and None is returned, be default False

[JoaoCarabetta]

Same on filters.clean_gps_nearby_points_by_speed(df_move, speed_radius=40.0) for speed. Is it m/s, or km/h?