Backup system changes

[Mr. NB]

Since the backup system is now capable of recognising cars involved, I'd like to propose some changes.

TBO chasing LRF or higher - first backup slot available immediately after failure to stop

Especially on faster tracks, LX6 or FZ5 have an advantage against, for example, an RB4. Removing the initial countdown timer could help balance that out.

Chases versus GTR - all four backup slots available immediately after failure to stop*

GTR's immense advantage in the form of slick tires currently pretty much makes them immune from chases—cops generally don't bother, because even an FZ5 can only last so many laps before the vast difference starts to show. If there's a car class that warrants immediate backup, it's GTR.

Equal car class (e.g. RB4 vs. FXO or FZ5 vs. FZ5) - no changes

*UF1, XFG and XRG weren't listed due to how rarely they participate in chases, but perhaps they should also have backup available immediately—pretty much anything out of their class is no fair match.

I feel these changes would add some dynamism to chases and allow cops to get engaged more often. While the current system does a good job of eliminating the auto-join apps, it also takes away some of the excitement and unpredictability that chases used to have.

Thanks!