Load handling from settings files

[AlexRazor1337]

Hello, this PR add abillity to load custom vehicle handling for new models from settings files. It uses straightforward approach with fixed code from this "Useful functions" article.

[Fernando-A-Rocha]

@AlexRazor1337 Thanks for your PR! The concept and implementation is nice, but I have a suggestion.

The parsing of the handling text should happen server-side when the handling= is read from the txt file, and there should be some validation to prevent missing or incorrect value types.

It doesn't make sense to parse and validate this client side each time the model is loaded because it causes more operations while it could be done once in the server. The server can store the handling values in a table format directly then the client can just loop through this table and do setVehicleHandling

[AlexRazor1337]

True, I'll try to refactor the code in this way

[Fernando-A-Rocha]

Thank you, feel free to voice your opinion. I'm very receptive

[Fernando-A-Rocha]

@AlexRazor1337 Please re-submit when ready :)