Move away from Conda

[LawrenceBorst]

Well things work, so doesn't need to happen per se. But it's unfortunate the Docker images are so needlessly large (Conda envs), slow to build (Conda dependency resolution), installation tends to break around Conda steps (on MacOS at least), and compilation of the Dockerfiles is slightly too prone to spontaneously breaking over time (hard to lock packages in Conda).

Besides, the commercial angle Conda is taking makes me prefer (1) a more open sourced solution or (2) installing system dependencies separately from the Python ones and use something very good for Python, like uv.