Example data - Brain MRI dataset

# Example data - Brain MRI dataset

This great PR https://github.com/napari/tutorials/pull/64 to the napari tutorials was made by partners @DaliaAymanAmeen and Dina for their RGSOC application. They use a beautiful MRI dataset of a human brain, and I think it would make a great example dataset for dask-image, too.

Link to main page: https://doi.org/10.5061/dryad.119f80q
License: This work is licensed under a [CC0 1.0 Universal (CC0 1.0) Public Domain Dedication](https://creativecommons.org/publicdomain/zero/1.0/) license.
Description: 7 Tesla MRI of the ex vivo human brain at 100 micron resolution. Includes axial, sagittal, and coronal imaging planes.

Direct download links (zip files containing a folder full of tiff images):
* 1.9GB zipped (expands to 4GB when unzipped). Synthesized_FLASH25_100um_TIF_Axial_Images.zip - https://datadryad.org/stash/downloads/file_stream/223913
* 1.9GB zipped (expands to 4GB when unzipped). Synthesized_FLASH25_100um_TIF_Coronal_Images.zip - https://datadryad.org/stash/downloads/file_stream/223914
* 1.9GB zipped (expands to 4GB when unzipped). Synthesized_FLASH25_100um_TIFF_Sagittal_Images.zip - https://datadryad.org/stash/downloads/file_stream/223915

PDF scan protocol file: https://datadryad.org/stash/downloads/file_stream/223924

MP4 movies of the data:
* VIDEO_4_100_MICRON_MRI_SYNTHESIZED_FLASH25_AXIAL.mp4 - https://datadryad.org/stash/downloads/file_stream/223929
* VIDEO_5_100_MICRON_MRI_SYNTHESIZED_FLASH25_CORONAL.mp4 - https://datadryad.org/stash/downloads/file_stream/223930
* VIDEO_6_100_MICRON_MRI_SYNTHESIZED_FLASH25_SAGITTAL.mp4 - https://datadryad.org/stash/downloads/file_stream/223931