Add option for time change speed to be 0

[TheeFrogmanlego]

I love setting the time around dawn or dusk on all the tracks but Gran Turismo 6 has a really crappy shadow flickering issue that ruins the experience on MOST time change tracks. I have come to the conclusion that the reason this is caused is due to time change. When I set it at 60, it moves very fluently. It starts to get choppy around 30, yet still some what acceptable. This is up until we reach time change ten , i think since the game calculates a slight moment that's not enough to be properly mapped it fluctuates back and forward causing this really horrendous wave flicker. By being gable to set a static time ( 0 time change speed) We get rid of this issue.