Deprecate use of scipy.misc.imread and scipy.misc.imsave
Deprecate use of scipy.misc.imread and scipy.misc.imsave

Summary:
* Deprecate use of scipy.misc.imsave and scipy.misc.imread (and those from scipy.ndimage package as well).
* Removed in 1.2.0 https://docs.scipy.org/doc/scipy-1.2.1/reference/generated/scipy.misc.imread.html and https://docs.scipy.org/doc/scipy-1.1.0/reference/generated/scipy.misc.imsave.html
* Use imageio.imwrite and imageio.imread instead.
* This diff updates most usages of except those in experimental folders.
* This diff does NOT fix existing lint/code/TARGETS issues.
* This diff does NOT autoformat codes.

Differential Revision: D19395500

fbshipit-source-id: 488d066fb49d9c7e061a589aa9b37b35928a40e6

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