Implement new ABI "MPIABI"

[eschnett]

The MPI standard 5.0 provides an official ABI for MPI. Both major MPI implementations (MPICH and OpenMPI) will soon release new versions which can, optionally, provide this ABI. In the far future I foresee us targeting just this ABI and not having to deal with the other ABIs.

This PR understands this ABI. The package MPIABI_jll already provides this ABI, using a beta version of MPICH 5.0.0.

[eschnett]

Waiting for #926

[eschnett]

The documenter fails because a link to mpich.org does not resolve. I don't know how to handle this.

[giordano]

Well, the links you added are broken.

[eschnett]

This is weird:

 Error: linkcheck 'https://mooseframework.inl.gov/moose/help/troubleshooting.html' status: 403.
└ @ Documenter ~/.julia/packages/Documenter/xvqbW/src/utilities/utilities.jl:47

The link resolves fine if I click on it, or copy-paste it. Maybe the web server does not accept connections from Github's servers?

[eschnett]

This is ready to be merged. The failing tests are all unrelated to this PR:

• The documentation encounters problems with the link checker and with cross references
• Builds with Julia 1.14 (nightly) are broken because Base introduced a new type Base.OffsetCConvert that we don't handle yet (Support Base.OffsetCConvert in Julia 1.14 #935)
• The buildkite tests fail because MPI doesn't start the process correctly; this is also unrelated.

[eschnett]

@vchuravy Do you mind if I tag new releases for MPI.jl and MPIPreferences.jl?

[giordano]

Documentation is still broken I believe

[luraess]

Is the broken doc related to #927 (comment) ?

[giordano]

Yes, I never had the time to look into it.

[luraess]

Doc should be fixed now.

[eschnett]

@giordano Do you mind if I tag new releases for MPI.jl and MPIPreferences.jl?

[giordano]

Should be good now.