Provide functionality for segmenting preop image in SliceTracker

[che85]

As of now only automatic segmentation with optional manual modification is supported within SliceTracker. It would be good to have a way to manually segment preop in SliceTracker including timestamps. In some cases, if the clinical user assumes that automatic segmentation might fail, this would be very helpful.

P.S. in mpReview we are not logging any information about the time during segmentation.