This involves setting up dependency management for dotenvx and friends via deno and actually setting up the Nix-based dev environment setup via https://devenv.sh (going to do the enterShell custom setup for auto-installing npm packages via deno later). We're also adding a gitignore here to ensure clutter aren't commited and consume a lot of repo storage both locally and on GitLab, plus to avoid leaking .env.keys stuff. Signed-off-by: Andrei Jiroh Halili <ajhalili2006@andreijiroh.dev>