Update build system for CMake 4 and OpenMP 17.0.1

[michaeltryby]

This pull request updates build tooling and dependencies for the SWMM Toolkit, focusing on modernizing CMake usage, updating OpenMP integration, and improving compatibility for macOS builds. The changes improve maintainability and ensure the project uses current best practices for building and linking libraries.

Build system modernization:

• Updated minimum required CMake version in swmm-toolkit/CMakeLists.txt from 3.17 to 4.0.2, ensuring compatibility with newer CMake features.
• Removed version pinning for build dependencies in build-requirements.txt, allowing installation of the latest compatible versions of setuptools, wheel, scikit-build, and cmake.

OpenMP integration improvements:

• Refactored extern/openmp.cmake to use OpenMP 17.0.1 (was 12.0.1), added explicit handling for LLVM CMake modules, and improved target linking and compiler options for better compatibility and maintainability.

macOS build compatibility:

• Changed the macOS build generator in setup.py from Ninja to Xcode and updated the deployment target from 10.9 to 11.0, improving support for recent macOS versions.

SWIG compile definitions:

• Updated SWIG compile definitions for output and solver targets in src/swmm/toolkit/CMakeLists.txt to explicitly set them to empty, which may resolve build warnings or errors related to macro definitions.

Submodule update:

• Updated the swmm-solver submodule to a newer commit, pulling in the latest changes from the solver codebase.

[michaeltryby]

Actions is failing on all platforms because the series are now end period inclusive. So that means the changes made to the C-API are carrying through the SWIG wrapper. This is a good sign!

[bemcdonnell]

@michaeltryby, not often enough is failure a sign of succsss. 😂😂😂