Deprecate AQT quantization in MaxText

[sarunsingla11722]

Description

This PR implements Phase 1 of the deprecation plan for Google's Accurate Quantized Training (AQT) library in MaxText in favor of its successor, Qwix. Qwix operates natively within the JAX ecosystem using a non-intrusive Interception API, supporting both QAT and PTQ without custom layer wrappers.
To ensure a smooth transition for enterprise customers and automated training scripts, AQT remains fully functional in this release but is explicitly marked as deprecated across core logic, configuration, and documentation. Full removal will occur in a future major release (Phase 2).

FIXES:b/512240084

Key Changes

• Core Logic (quantizations.py): Added max_logging runtime warning alerting users that AQT is deprecated and advising migration to Qwix (use_qwix_quantization=True).
• Configuration (base.yml): Updated inline documentation for use_qwix_quantization to mark the legacy AQT default as deprecated.
• Documentation (quantization.md, supported_models_and_architectures.md): Added prominent deprecation callout banners and updated feature lists to recommend Qwix.

Tests

Verification & Testing

• Unit Tests: Verified existing quantization unit tests pass and QuantizationTest.test_aqt_quantization successfully emits the deprecation warning.
• Smoke Tests: Confirmed end-to-end INT8 training completes successfully under legacy AQT defaults while logging the deprecation warning.

If the change fixes a bug or a Github issue, please include a link, e.g.,:
FIXES: b/123456
FIXES: #123456

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Tests

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Checklist

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• I have made or will make corresponding changes to the doc if needed, including adding new documentation pages to the relevant Table of Contents (toctree directive) as explained in our documentation.

[gobbleturk]

potentially this should go in types.py instead but prolly fine here

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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