Update QAT tutorial

[andrewor14]

This commit refreshes the QAT tutorial to make it reference new APIs and classes, remove outdated configs, and fix broken commands.

[pytorch-bot]

🔗 Helpful Links

🧪 See artifacts and rendered test results at hud.pytorch.org/pr/pytorch/torchtune/2396

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[andrewor14]

@ebsmothers @joecummings

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 0% with 3 lines in your changes missing coverage. Please review.

Project coverage is 23.45%. Comparing base (f67ccda) to head (b6ed7b1).
Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
recipes/quantize.py	0.00%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2396      +/-   ##
==========================================
- Coverage   23.46%   23.45%   -0.01%     
==========================================
  Files         373      373              
  Lines       22405    22416      +11     
==========================================
+ Hits         5257     5258       +1     
- Misses      17148    17158      +10     

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