Simplify derailing logic, derail reason enum

- The `TMoverParameters::derail()` function has been renamed to `::Derail()`, with a capital D.
- All derail events now use that function.
  - Simplified and unified the logic behind different derail types.
  - The `dtrack_freerail` track type is now slightly increasing the chance of derailing on a tight curve, as it was the intention.
- A new `DerailReason` enum has been created which holds all derail types.
- The `DerailReason` field in the `TMoverParameters` class has been removed.
  - This was a transient field which is not necessary anymore.
  - The logging functionality as such has been moved from `DynObj.cpp` to `Mover.cpp`.

vehicle/DynObj.cpp

@@ -4265,27 +4265,6 @@ bool TDynamicObject::Update(double dt, double dt1)
 		MoverParameters->InactiveCabPantsCheck = false;
 	}
 
-
-    if (MoverParameters->DerailReason > 0)
-    {
-        switch (MoverParameters->DerailReason)
-        {
-        case 1:
-            ErrorLog("Bad driving: " + asName + " derailed due to end of track");
-            break;
-        case 2:
-            ErrorLog("Bad driving: " + asName + " derailed due to too high speed");
-            break;
-        case 3:
-            ErrorLog("Bad dynamic: " + asName + " derailed due to track width");
-            break; // błąd w scenerii
-        case 4:
-            ErrorLog("Bad dynamic: " + asName + " derailed due to wrong track type");
-            break; // błąd w scenerii
-        }
-        MoverParameters->DerailReason = 0; //żeby tylko raz
-    }
-
     if( MoverParameters->LoadStatus ) {
         LoadUpdate(); // zmiana modelu ładunku
     }