ENH: add specific streaming policy for StreamingShrinkImageFilter, to avoid reading all the data

Add a specific ImageRegionSplitter implementation :
- which generates tiles of 1 pixel height
- with the same tile width as the one computed with the meory estimator
- with a tile width aligned on the ShrinkFactor
Add a specific StreamingManager implementation which make use of the StreamingShrinkImageRegionSplitter
Make this specific StreamingManager the default implementation used by StreamingShrinkImageFilter