[WIP] backend: (x86) add kmov ops

[superlopuh]

While I was implementing this I realised that the x86 dialect would benefit from a refactor to carry the bitwidth of the operands on the op rather than on the operands.

[codecov]

Codecov Report

❌ Patch coverage is 90.58824% with 8 lines in your changes missing coverage. Please review.
✅ Project coverage is 85.94%. Comparing base (30009a7) to head (23512e0).

Files with missing lines	Patch %	Lines
xdsl/dialects/x86/ops.py	90.58%	8 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #5488   +/-   ##
=======================================
  Coverage   85.93%   85.94%           
=======================================
  Files         383      383           
  Lines       55150    55235   +85     
  Branches     6343     6345    +2     
=======================================
+ Hits        47392    47469   +77     
- Misses       6247     6255    +8     
  Partials     1511     1511           

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