Refactor `generic_float` to handle `E8M0` type

[CharlieL7]

DOR (Definition of Ready)

Ready.

Description

• Need to support E8M0 type for better handling of MX block scales in MIGX.
• Current generic_float implementation doesn't allow for having zero mantissa bits and no sign bit.
• Discussed refactor of generic_float to have a specialization for this case and similar ones.

DOD (Definition of Done)

• E8M0 type handed in MIGX through generic_float