[issue1199] Add Gurobi support.

[TravisRiveraPetit]

This PR adds Gurobi 13.0.x as a new LP/MIP solver backend and tests it on Ubuntu, macOS, and Windows. It also expands macOS, Ubuntu, and Windows CI workflows so that all implemented solver backends (i.e., Gurobi, CPLEX, and SoPlex) are tested on each platform.

Main changes

Documentation

BUILD.md was updated with instructions on how to set up Gurobi on Ubuntu, macOS, and Windows.

Gurobi

• Add a Gurobi implementation of the LP solver interface.
• Add FindGurobi.cmake to locate Gurobi headers and libraries.
• Add Gurobi header to the clang-tidy ignore list
• Add Tox environment for Gurobi

Ubuntu CI

• Add a Gurobi workflow

macOS CI

• Update tested macOS versions from 14/15 to 15/26.
• Update Python version from 3.14 to 3.10, matching the version used for Ubuntu.
• Add a Gurobi workflow
• Add a CPLEX workflow.
• Add a SoPlex workflow. The tested SoPlex version is 7.1.6 instead of 7.1.0 because the latter has a known compilation bug on macOS. See https://sources.debian.org/src/soplex/7.1.6%2Bdfsg-3/CHANGELOG.

Windows CI

• Add a Gurobi workflow
• Add a SoPlex workflow
• Fix a conflict between Windows ERROR macro and SoPlex's ERROR enum.

Repository secrets

The following secrets were added to the repository:

• GUROBI1302_LINUX_URL
• GUROBI1302_OSX_URL
• GUROBI1302_WINDOWS_URL
• GUROBI_LICENSE_URL
• CPLEX2220_OSX_URL