Added an ability to use the headlights on all the vehicles in the game, these headlights are also more customizable.

[Wikot235]

You can now enable the headlights on all the vehicles in the game with a key that is bound to the "impulse 100" command.
This PR also adds new keyvalues for all the vehicles in the game.

1. HeadlghtScale - it allows you to make the light much bigger, it's very buggy at high values though.
2. HeadlightColor - it allows you to make the light any color you want.

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Does this PR close any issues?

It closes the #440 issue.

PR Checklist

• My PR follows all guidelines in the CONTRIBUTING.md file
• My PR targets a develop branch OR targets another branch with a specific goal in mind