SG-43456 Add MEDM abstractions and utilities

[carlos-villavicencio-adsk]

Classes to represent models and required utilities. We will consider moving them into a directory to improve code-organization

• Entity model
• Latest publish model
• Publish History model
• Shared cache
• Thumbnail service
• MEDM Utils

ℹ️ This should not affect or break the loader functionality.

[codecov]

Codecov Report

❌ Patch coverage is 0% with 783 lines in your changes missing coverage. Please review.
✅ Project coverage is 15.40%. Comparing base (fe5e5b9) to head (de8d721).

Files with missing lines	Patch %	Lines
python/tk_multi_loader/medm/latestpublish_model.py	0.00%	284 Missing ⚠️
...ython/tk_multi_loader/medm/publishhistory_model.py	0.00%	195 Missing ⚠️
python/tk_multi_loader/medm/entity_model.py	0.00%	157 Missing ⚠️
python/tk_multi_loader/medm/thumbnail_service.py	0.00%	79 Missing ⚠️
python/tk_multi_loader/medm/utils.py	0.00%	41 Missing ⚠️
python/tk_multi_loader/medm/shared_cache.py	0.00%	20 Missing ⚠️
python/tk_multi_loader/medm/__init__.py	0.00%	7 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #137      +/-   ##
==========================================
- Coverage   19.72%   15.40%   -4.32%     
==========================================
  Files          35       42       +7     
  Lines        2794     3577     +783     
==========================================
  Hits          551      551              
- Misses       2243     3026     +783     

Flag	Coverage Δ
Linux	15.40% <0.00%> (-4.32%)	⬇️
Python-3.10	15.40% <0.00%> (-4.32%)	⬇️
Python-3.11	15.40% <0.00%> (-4.32%)	⬇️
Python-3.13	15.40% <0.00%> (-4.32%)	⬇️
Python-3.9	15.40% <0.00%> (-4.32%)	⬇️
Windows	15.40% <0.00%> (-4.32%)	⬇️
macOS	15.40% <0.00%> (-4.32%)	⬇️

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