Fix distance_to_polyline function in position.rs

[nbuffon]

The current implementation uses geo:0.27 euclidean distance to get the distance between a point and a "polyline" object composed of several positions

The implementation has been here due to refactoring adaptation to the new Positionstruct and testing it is required

Problem is that the following unit tests fail
Is it dues to data or implementation ?

    macro_rules! test_distance_to_line {
        ($test_name:ident, $position:expr, $line:expr, $expected:expr) => {
            #[test]
            fn $test_name() {
                let epsilon = 1e-7;

                let distance = distance_to_line(&$position, $line);
                let delta = (distance - $expected).abs();

                assert!(
                    delta <= epsilon,
                    "Actual: {} (expected: {}",
                    distance,
                    $expected
                );
            }
        };
    }
    test_distance_to_line!(
        fifty_meters_north,
        position_from_degrees(48.62564545754, 2.24150940001, 0.),
        &[position_from_degrees(48.62519582726, 2.24150938995, 0.),
            position_from_degrees(48.62519580005, 2.24175355955, 0.)],
        50_f64
    );
    test_distance_to_line!(
        eigthen_meters_east,
        position_from_degrees(48.62519580005, 2.24175355955, 0.),
        &[position_from_degrees(48.62519582726, 2.24150938995, 0.),
            position_from_degrees(48.62564545754, 2.24150940001, 0.)],
        18_f64
    );