Improve package/version management by moving to pixi

[irm-codebase]

What can be improved?

Version management in python can be a bit of a hassle sometimes, specially for projects mean to run in different platforms such as Calliope.

Our current approach to the dev and base environments leaves us open to many conflicts because they are manually inputted, and lack a lock file.

pixi is quickly becoming one of the most popular tools to ensure stability in projects using conda: https://github.com/prefix-dev/pixi/ and it even has full compatibility with pyproject.toml files.

I think we should consider moving to it to make collaboration less painful in the long term.

What do you think?

Version

v0.7.0.dev3