Deprecate broken ImagingRetinotopy module

[rly]

Motivation

Companion PR to NeurodataWithoutBorders/nwb-schema#565
Closes #1053.

Checklist

• Did you update CHANGELOG.md with your changes?
• Have you checked our Contributing document?
• Have you ensured the PR clearly describes the problem and the solution?
• Is your contribution compliant with our coding style? This can be checked running flake8 from the source directory.
• Have you checked to ensure that there aren't other open Pull Requests for the same change?
• Have you included the relevant issue number using "Fix #XXX" notation where XXX is the issue number? By including "Fix #XXX" you allow GitHub to close issue #XXX when the PR is merged.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (5c760da) 92.01% compared to head (e43eb94) 91.84%.

Additional details and impacted files

@@                 Coverage Diff                  @@
##           nwb-schema-2.7.0    #1813      +/-   ##
====================================================
- Coverage             92.01%   91.84%   -0.17%     
====================================================
  Files                    27       27              
  Lines                  2641     2587      -54     
  Branches                693      687       -6     
====================================================
- Hits                   2430     2376      -54     
  Misses                  138      138              
  Partials                 73       73              

Flag	Coverage Δ
integration	71.12% <0.00%> (+0.39%)	⬆️
unit	83.41% <100.00%> (-0.34%)	⬇️

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