new feature: add ":pre-initialize-fn" function which does python package managent using 'uv sync'"

[behrica]

``see here for details:
https://clojurians.zulipchat.com/#narrow/stream/215609-libpython-clj-dev/topic/poetry.20install.20--sync

I can do a PR, if you are interested

This would be full optional, and triggers only if specified inside python.edn:

{:python-executable ".venv/bin/python"
:pre-initialize-fn libpython-clj2.python.poetry/setup!}

[cnuernber]

That design looks fine - PR is welcome :-).