Introduce 3.13 and drop 3.8 Python image generation

Python pre-releases

• Use rc tag, unstable Python version
• Introduce with gcc and libffi-dev installed in the meantime
• Install pre-commit and git on 3.13 image.

Python stable release

• Remove gcc and libffi-dev once no longer necessary, once Py3.13 wheels are provided to run poetry install
• Remove rc tag once Python 3.13 is released as stable
• Drop Python 3.8 image generation
• Use Alpine Linux, because Pendulum does not provide 3.13 wheels and Pendulum requires up-to-date Rust toolchain, which can be found in Alpine 3.20, but not in Debian 12. Switch images to Alpine (#11)
• Remove Rust toolchain installation once Pendulum provides 3.13 wheels.

Default image usage switch?

• Remove pre-commit and git installation from 3.12 image, once no longer default image in DuniterPy and Silkaj projects.

Post

• Create follow-up ticket for Py 3.14/3.9: Introduce 3.14 and drop 3.9 Python image genera... (#12 - closed)