docs: Add PII annotations

[bmtcril]

Per OEP-30 these annotations should live with their models. I'm just moving them from the edx-platform safelist to their correct home.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 100.00%. Comparing base (20e4e6e) to head (4ede87d).
Report is 8 commits behind head on master.

Additional details and impacted files

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##            master      #388   +/-   ##
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  Coverage   100.00%   100.00%           
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  Files           16        16           
  Lines          433       433           
  Branches        47        47           
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  Hits           433       433           

Flag	Coverage Δ
unittests	100.00% <ø> (ø)

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[kdmccormick]

LGTM, but consider releasing a patch version otherwise this might never go out :P