GridPatchDataset to support patch level transformations

[wyli]

the current GridPatchDataset supports transformations at image level

MONAI/monai/data/grid_dataset.py

Lines 26 to 38 in 2eada01

	class GridPatchDataset(IterableDataset):
	"""
	Yields patches from arrays read from an input dataset. The patches are chosen in a contiguous grid sampling scheme.
	"""
	def __init__(
	self,
	dataset: Sequence,
	patch_size: Sequence[int],
	start_pos: Sequence[int] = (),
	mode: Union[NumpyPadMode, str] = NumpyPadMode.WRAP,
	**pad_opts: Dict,
	) -> None:

this ticket looks for options of patch level transforms to be applied before yielding the patches

context:
#1473