[Draft] Build with meson-python backend

[whophil]

Purpose

Build with meson-python backend.

This simplifies the build system, allowing for removal of nearly all code in setup.py, which is now replaced with pyproject.toml. In addition, the meson.build files are cleaned up where possible, and updated to use the latest helpful patterns from scipy's meson files.

TODO:

• add dynamic version
• no IPOPT in Linux builds?

Expected time until merged

Type of change

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (non-backwards-compatible fix or feature)
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no API changes)
• Documentation update
• Maintenance update
• Other (please describe)

Testing

Existing tests.

Checklist

• I have run flake8 and black to make sure the Python code adheres to PEP-8 and is consistently formatted
• I have formatted the Fortran code with fprettify or C/C++ code with clang-format as applicable
• I have run unit and regression tests which pass locally with my changes
• I have added new tests that prove my fix is effective or that my feature works
• I have added necessary documentation