haversine_distance
Return the distance of the line using haversine formula
https://en.wikipedia.org/wiki/Haversine_formula
Units are meters.
Examples:
haversine_distance(to_line('LINESTRING (1 2, 1 3)'))
-- Result: "111195.0802335329"
haversine_distance(to_multiline('MULTILINESTRING ((10 10, 20 20, 10 40), (40 40, 30 30, 40 20, 30 10))'))
-- Result: "8443359.868161995"
l -> number