Adopt uv to manage packages

[n-batalha]

While we have a Python project, we adopt some best practices to help make sure the builds are reproducible and do not suddenly break (we currently see some errors in logs, as the deps used before have changed, but the requirements file just installs the latest, so more breakages can occur whenever caches expire).

Also now both local and deployment dependencies and Python versions are the same, so we're more confident how it renders locally is the same as when deployed.

Python's official tool is pipenv https://packaging.python.org/en/latest/tutorials/managing-dependencies/#managing-dependencies but the community seems to be converning on uv.

I only couldn't easily test GitHub Actions changes, but I commit to fix if only revealed once merged.

[birdybro]

Interesting, I'll have to learn more about uv, wasn't aware of it. Yeah, sometimes I don't update these until there is an actual problem or error message, hence things being out of date. I'll evaluate all this later on when I'm less busy, sorry for the delay.