Expose certain PP5 context properties in PP5EnrollTransform

@JordanCheney @mmtaborsky While the default PP5 settings are good for getting the maximum recognition performance under all conditions, they are non-ideal when enrollment speed is a concern. This PR allows certain context properties to be set in the algorithm string that are particularly relevant for changing the speed/accuracy tradeoff.
@bklare @imaus10 It appears that these optimizations have no impact of LFW accuracy and cut registration speed by ~2/3.