Randomly spawn civilian vehicles in towns and cities

* Every ten seconds, check villages, towns and cities near live players
and spawn one or more civilian vehicles somewhere near the roads in that
area. The vehicles will usually be moderately damaged and have little
fuel.
* Add BLOL_fnc_ambiance_civilianVehicles.
* Add BLOL_fnc_ambiance_randomVehicleDamage.
* Add BLOL_fnc_ambiance_randomVehicleFuel.
* Add BLOL_fnc_players_nearbyLocations.