`devShells`: Create composable `devShells` for environments

[Sam Lehman]

devShells

Personal

• Nix
• NixOS
• Nix secrets agenix / sops-nix
• nixpkgs updater / maintainer
• Kubernetes / Helm
• Docker / Podman
• WINE / Bottles / Windows VMs
• GTK development
• Mobile Linux development & flashing

Upstream

• handlr
• farside
• UltimateTrainingModpack

Ideas

• flake-parts flakeModules?
• organist?
• devenvs?