[ENH] - Use rattler and pixi instead of standard conda tooling

[nkaretnikov]

Feature description

See this talk from PackagingCon 2023: https://cfp.packaging-con.org/2023/talk/V8R3D7/ How we used Rust to modernize the conda ecosystem Bas Zalmstra

Value and/or benefit

Based on my conversation with Bas after the conference:

• rattler is faster than mamba due to optimizations they were able to do
• should be compatible in terms of features (that we use)
• pixi doesn't write to system files (no changes to .bashrc or similar necessary - can be annoying to users or on CI)
• written in Rust, so easy to modify compared to C solver libs (I love Rust), which is how they managed to optimize it better
• rattler has python bindings
• new tooling, without legacy code
• prefix people are friendly and open to patches if necessary.

Anything else?

This is just an idea to explore, not an immediate call to action.

[nkaretnikov]

Alternatively, if we cannot integrate this tooling right away, we just need to see what it does differently and port these ideas to conda-store.

[jaimergp]

Noting here that pixi (iow rattler) is going to integrate uv as the PyPI resolver (instead of resolvo). Maybe the safest way to benefit from this is to wait for this integration to happen, and/or enable conda-lock to use uv instead of poetry.