[BUG] Taxijob distance calculation exploitation

[adweex]

Describe the bug
Taxijob calculates distance well, however during npc missions the calculation is exploitable. You don't really have to do the jobs because you can take the npc anywhere you would like while getting money for it.

To Reproduce
Steps to reproduce the behavior:

1. Start an npc mission and don't go to the objective just drive around freely

Expected behavior
NPC should react if its not getting closer to the destination or we should stop the meter if player goes the wrong direction.

As far as i know there is no possible way to calculate distance just like the GPS do, or use that value.
One solution could be drawing an " airline " between the pickup point and destination point and use that value. (not the best option but solves the exploitation).

**Screenshots $$$ **
He will never return home

[artur-michalak]

I have two ideas:

• specifying the maximum distance of the route in the config
• multiplier of the distance in the config as maximum distance. Example distance = 4 miles, with multiplier 1.5, npc will discontinue the service when you exceed 4 * 1.5 miles (default multiplier 1.5)
  all options with some randomization.