Metal Detector Rework

In the current state the metal detector mechanic is less than satisfying and it feels like the map/mission designers did not know how to utilise it, and choose not to anymore. The issues:

• Detector can be activated only once at the time, forcing the player to make an incoventient stops ever so often.
  
• Range is relatively low and most of the times, player sees the objective cargo before even using the detector.
  
• The cargo landmark is visible on the minimap, revealing its location prematurely before player even uses the detector.

I propose several changes to make the detector have more actual sense and mission potential:

• Instead of using detector once at the time, draining a set amount of fuel, allow the player to turn the detector on and move the truck at the same time, draining the fuel at a constant rate. Detector stops working only if player chooses to deactive it or it runs out of fuel.
  
• Keep track of the distance between a truck with activated detector and all of the objective cargoes; Make the detector play a noise at a rate/frequency faster the closer the player gets to either of the objective cargoes.
  
  • Also have a 3D "wave effect" of the produced sound around the truck, so the player also has a visual confirmation hint of the detector working; and/or add a light beacon that flashes at an appropriate rate to the distance.
  • Allow to disable detector noise and flashing effect for the players that choose to in the game settings.
• Do NOT display neither icon nor map landmark of the objective cargo, until player gets close enough to it.
  
• Have the detector's range radius of at least 100 meters for it to start detecting the cargo and giving sound/visual hints.
  
• Cargo gets fully revealed (with its icon and landmark) when player is next to it (less than 20 meters).
  
• Optionally: For each mission with metal detector, have large +150 meters of radius indicator zones as to where to look (similar to Hard Mode).
  
• Optionally: When detector is used during an active detector mission, leave on the minimap a 20m radius trail of where player has already driven while the detector was active, to help the player with the search.