Allow CUDA build with bazel

[TendTo]

Add the option to build Highs (more precisely cupdlp) with CUDA using Bazel as the build system.
For the CUDA build to be selected, the following 3 must be true:

• a CUDA toolchain is detected on the system
• the flag @rules_cuda//cuda:enable=False is NOT used (true by default)
• the flag --//:cupdlp_gpu is used

I hadn't the chance to test it on many systems with different configurations, but the little testing I did seem to confirm that this small change works as expected.
Let me know if there are any issues with it.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 79.70%. Comparing base (71e327a) to head (44f5b6c).
⚠️ Report is 65 commits behind head on latest.

Additional details and impacted files

@@            Coverage Diff             @@
##           latest    #2554      +/-   ##
==========================================
+ Coverage   79.66%   79.70%   +0.04%     
==========================================
  Files         346      346              
  Lines       86430    86417      -13     
==========================================
+ Hits        68854    68882      +28     
+ Misses      17576    17535      -41     

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[galabovaa]

My local tests passed as well! Thank you, @TendTo, for this small but important update!

[galabovaa]

@TendTo this code breaks the highs update in bazel-central-registry. I will have to modify it somehow, so

bazel_dep(
    name = "rules_cuda",
    version = "0.2.5",
)

is only optional in MODULE.bazel or moved to a separate file.

Could you tell me a little bit more about how you are using HiGHS with bazel in your project?

[TendTo]

Interesting, could you share some more details on how the dependency breaks the update? I would assume that the dependency (rules_cuda) is only pulled if you actually need it, and it should not impact anything else, but there is clearly some flaws in my assumption.

I was planning on using Highs mostly as a configurable LP solver, since it supports Simplex, IPM and pdlp. Moreover, being open source, it would not require the user to have a licence and I was also considering statically linking it if needed.

[galabovaa]

Actually, I think it's fine. The failure was my mistake, I needed to update one more file in bcr. I will test this a bit more locally with and without NVvidia, but I think it will go OK.

I was curious if you are just using bazel to build the highs library or binary or if your parent project is also bazel-based. So far, the bazel build has been used mostly for OR-Tools, at least as far as we know. It is great to hear that you have decided to try HiGHS and thank you again for your contribution!