get emacs to use a nix-managed project's development environment

Emacs packages will respect project-specific development environments as specified in the directory's .dir-local.el. It sure would be nice to have this generated by a nix-managed project's flake - a template listing

• the devShell as the shell to compile in
• the right environment to look for dynamic libraries in (how would this even work?)
• the right LSP server (eglot-workspaceconfiguration)