[WIP] [PyTorch] Support dtype casting in fused adam

[Wong4j]

Description

FusedAdam updates the params in-place currently. This PR adds dtype casting in FusedAdam kernel, in addition to updating the master params in-place, but also can update extra model params. The extra params can be of bf16, fp16, fp8 type.

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)
• [x] 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 refractor

Changes

Please list the changes introduced in this PR:

• Change A
• Change B

Checklist:

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