Swap hlac colors with mg+okmg colors

Swap hlac colors with mg+okmg colors

Once again there are many reasons to make this change:
- All those listed in d12dc1c164 (better that only one of the two weapons uses an identical color rather than both),
- Hlac now shoots green bullets due to d12dc1c164,
- Machinegun bullet trails are yellow-orange,
- Machinegun bullet casings are yellow-ish,
- The wpcolor of Machinegun is already yellow,
- ... meaning the crosshair with `crosshair_color_special 1` is already yellow,
- The _simple simpleitems color for machinegun is already yellow,
- Making Overkill Machinegun orangey brings it closer to the Overkill Heavy Machinegun's color,
- Etc.
This will have to be followed up with a mediasource MR.