Feature/issue 233 sorting variable arg in cli

[danielfromearth]

GitHub Issue: #233

Description

Renamed time_variable to sorting_variable to better reflect its purpose. Exposed this variable in the CLI, and moved the default for TEMPO into the Harmony adapter and out of the stitchee core code.

PR Acceptance Checklist

• Unit tests added/updated and passing.
• Integration testing
• CHANGELOG.md updated
• Documentation updated (if needed).

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📚 Documentation preview 📚: https://stitchee--238.org.readthedocs.build/en/238/

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 86.02%. Comparing base (0e53d8f) to head (cf9b31d).

Additional details and impacted files

@@             Coverage Diff             @@
##           develop     #238      +/-   ##
===========================================
+ Coverage    83.46%   86.02%   +2.56%     
===========================================
  Files           11       11              
  Lines          641      644       +3     
===========================================
+ Hits           535      554      +19     
+ Misses         106       90      -16     

Flag	Coverage Δ
integration	45.03% <75.00%> (?)
unittests	83.54% <100.00%> (+0.07%)	⬆️

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