[PyTorch] Rename and clean up MXFP8 recipe class

[timmoon10]

Description

#1442 changed BlockScaling to MXFP8BlockScaling, a big improvement since a certain other 1x128 block scaling recipe has been in the news. That said, it is still a redundant name since MXFP8 will never not use block scaling. This PR changes the name to MXFP8Recipe and makes several other non-functional quality-of-life improvements.

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

• Rename MXFP8BlockScaling to MXFP8Recipe and MXFP8BlockScalingRecipeState to MXFP8RecipeState
• Rename recipe type checkers to is_delayed_scaling and is_mxfp8 to make it more obvious they are boolean
• Make is_delayed_scaling and is_mxfp8 class variables instead of functions
• Use is_delayed_scaling instead of is_mxfp8 when dealing with delayed scaling logic

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

[timmoon10]

Pipeline 23277614