multi-platform pixi bootstrapping supporting jax-cpu and jax-gpu

[vkmvkmvkmvkm]

• bootstrapping script from ./scripts/bootstrap.sh

  • tested locally on osx arm
  • tested remotely on gcp linux64- osx64-arm

• distinct python virtual environments:

  • "pixi run -e gpu python" for jax gpu version
  • "pixi run python" for jax cpu version, by default

• configured via ./pyproject.toml

[vkmvkmvkmvkm]

@sritchie --- [[ Not urgent, weekend hacking :) ]] Aaron and I encountered a gitStream.cm failure; see above. Is it possible for us to get some help from you to debug this?

@sharlaon --- FYI in the interim we will keep working on our branch to develop pedagogical features.

[eightysteele]

@vkmvkmvkmvkm I just noticed that this isn't actually blocking the merge. @sharlaon this is ready for you to review and merge, but no pressure!

[sritchie]

@vkmvkmvkmvkm its not blocking a merge so ignore for now, we can look this week.