[WIP][Common,pytorch] Add FlexQuantizer for customized quantization via CuTeDSL

[kainzhong]

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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• The functionality is complete
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• 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

[kainzhong]

Probably a bad idea. Should take a look at how this is used and figure it out. If row-wise and column-wise quantization is different what should this be then...?

[kainzhong]

Closed in favor of #2817 . Looks like I can build flex quantization on top of his HybridQuantizedTensor which will same me lots of trouble integrating with the pytorch ecosystem.