Pre-install: devenv.sh

[shyim]

Is your feature request related to a problem? Please describe

Not really

Describe the behaviour you'd like

Devenv allows to describe a developer environment in declarative way in Nix. The configuration works on any Unix environment. As Nix/Cachix is already pre-installed, it's not a huge step to pre install also devenv.

Describe alternatives you've considered

Build my own docker image