[Please-take-over] core: Add BitEnumAttribute

[zero9178]

The BitEnumAttribute is meant to be the equivalent of BitEnumAttr in MLIR: https://github.com/llvm/llvm-project/blob/e67f2cc3fc38cec2041cfb197ac4688ed3d16e7e/mlir/include/mlir/IR/EnumAttr.td#L266
It allows defining an attribute which in abstract is a set of flag values where each flag value is defined within an enum.

The base class is meant to be easy to use like EnumAttribute and automatically define suitable parsers and printers.
For an in-tree user that is converted by this PR see FastMathAttr in the LLVM and arith dialects.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 89.61%. Comparing base (6252a84) to head (8b06f3f).

Additional details and impacted files

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##             main    #2617      +/-   ##
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- Coverage   89.62%   89.61%   -0.01%     
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  Files         358      358              
  Lines       45676    45702      +26     
  Branches     6888     6889       +1     
==========================================
+ Hits        40935    40957      +22     
- Misses       3687     3689       +2     
- Partials     1054     1056       +2     

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[superlopuh]

Ah, @zero9178, now it's just the formatting failing, should be easy enough to get working locally for you, then should be good to open up for review when you're ready

[math-fehr]

Currently taking over, I'm splitting this PR in multiple ones as well

[superlopuh]

@math-fehr what's the latest on this?

[math-fehr]

Sorry about this. I merged part of it (the parsing for enums) but now I don't have time anymore to continue it in the next month.
If someone wants to take over, please do