Remove scipy face dataset from testing

[j-c-c]

Remove scipy's face image from testing in favor of a generated image.

1. Replaced face with generated image in test_image.py
2. Removed unused import of face in test_starfileio.py, along with other unused code
3. There is still one remaining use of face in a gallery tutorial

Resolves #1372

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.21%. Comparing base (921de02) to head (3d07836).
⚠️ Report is 4 commits behind head on develop.

Additional details and impacted files

@@           Coverage Diff            @@
##           develop    #1373   +/-   ##
========================================
  Coverage    90.21%   90.21%           
========================================
  Files          135      135           
  Lines        14658    14658           
========================================
  Hits         13223    13223           
  Misses        1435     1435           

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[garrettwrong]

lol, this pr installed the old packages into the fresh CI envs and is failing because now both versions are installed. I'll need to fix the environments again. Please update your branches before you push them.

[garrettwrong]

So long as you feel that simulated image is realistic enough to capture all the behaviors we might want to test now and in the future... this is good, thanks for removing.

[j-c-c]

So long as you feel that simulated image is realistic enough to capture all the behaviors we might want to test now and in the future... this is good, thanks for removing.

Ok, made one small change so the image is not symmetric. Realized that one of the tests is flipping the image along axes and in some cases the flipped image is allclose to the original image (probably not a great characteristic for testing).

[garrettwrong]

Great, thanks!

[garrettwrong]

We can go ahead an merge this one when you are ready. Thanks