Zarr/H5 post-processing for instance segmentation

We need to implement `after_merge_patches_by_chunks_proccess_patch` function ([here](https://github.com/danifranco/BiaPy/blob/97603fbf4b94a22112c6504105fd13cb06d9a954/engine/instance_seg.py#L373)). Instance creation needs to be done by patches and then merge. Example in [cellpose code](https://github.com/MouseLand/cellpose/blob/main/cellpose/contrib/distributed_segmentation.py).