Add models.encodings.binary_encoder for real-valued data

[renatomello]

Will generalize to complex-valued data in a separate PR soon.

Checklist:

• Reviewers confirm new code works as expected.
• Tests are passing.
• Coverage does not decrease.
• Documentation is updated.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 99.68%. Comparing base (9fa2fb1) to head (21e29d5).

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #1551   +/-   ##
=======================================
  Coverage   99.67%   99.68%           
=======================================
  Files          76       76           
  Lines       11234    11272   +38     
=======================================
+ Hits        11198    11236   +38     
  Misses         36       36           

Flag	Coverage Δ
unittests	99.68% <100.00%> (+<0.01%)	⬆️

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