Add pyproject.toml to python bindings

[twizmwazin]

Adding a pyproject.toml allows tools like python-build and pip to know how to build a python package. Maturin is already very integrated with pyproject.toml. With this change, users will be able to install LibAFL from source into their python environment with just pip install git+https://github.com/AFLplusplus/LibAFL.git#subdirectory=bindings/python. Optionally, wheels could then be published to PyPI, and users would be able to get started with just pip install pylibafl, or similar.

[domenukk]

This is cool! Do we want to also switch to pip from maturin in CI?

[twizmwazin]

I can try at switching it over.

[domenukk]

It also still seems to fail:

Run cd ./bindings/pylibafl && python3 -m venv .env && . .env/bin/activate && maturin develop && ./test.sh
💥 maturin failed
  Caused by: pyproject.toml is invalid
  Caused by: pyproject.toml is not PEP 517 compliant: invalid type: string "MIT OR Apache-2.0", expected a table with 'file' or 'text' key
Error: Process completed with exit code 1.

[twizmwazin]

@domenukk I've updated the CI as you suggested and have fixed the invalid license field. It seems as of right now pyproject.toml doesn't support specifying multiple license values directly. An alternative would be to create another license file that has both licenses contained and specify that file, but for now I've just marked both licenses in the classifiers field.

[domenukk]

Thank you!