Enable post-RHT amax estimation with separate amax scale kernel

[negvet]

Description

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Fixes # (issue)

Type of change

• Documentation change (change only to the documentation, either a fix or a new content)
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Infra/Build change
• Code refactoring

Changes

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Checklist:

• I have read and followed the contributing guidelines
• The functionality is complete
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[negvet]

/te-ci

[zhongbozhu]

Having a separate amax scale API automatically means that we need a grouped API for MOE and therefore not a good choice moving forward. Can we fuse the amax scaling as part of the FP4 quantize kernels via the quantization config struct? Whenever we change the numeric for Dense, we have to change it for MOE.