Add Manual Update extension

[weicai995]

Add an extension to the DelayType and PlayerLoopTiming

Here is an example to create a manual type task.

UniTask.Delay(TimeSpan.FromSeconds(value), DelayType.ManualTime, PlayerLoopTiming.ManualUpdate,
                cancellationToken);

Use method PlayerLoopHelper.ManualUpdate(); to manually update this type of task. It provides a good way to keep synchronization in Lockstep sync.

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[zh99998]

this feature is very useful on Deterministic Lockstep RTS