[misc] shell.nix
[misc] shell.nix

Simply `nix-shell shell.nix` in the repository root to go into a
shell where all RSG dependencies are installed.

This can be automated whenever the directory is entered via direnv.
https://github.com/direnv/direnv/wiki/Nix

mquinson/remote-simgrid,mquinson/remote-simgrid,mquinson/remote-simgrid