Update main.lua for code improvement and disable controls while engine off

[warlikeprince]

Describe Pull request
It is the small code improvement for repetitive code. As well as i added the code to check for the weather engine is on or off, If engine is off then it disable the vehicle control actions like acceleration, braking, left turn and right turn.

If your PR is to fix an issue mention that issue here
qbcore-framework/qb-smallresources#464
#256
#257

Questions (please complete the following information):

• Have you personally loaded this code into an updated qbcore project and checked all it's functionality? [yes]
• Does your code fit the style guidelines? [yes]
• Does your PR fit the contribution guidelines? [yes]