My tandoor-recipes fix was merged upstream, so remove the overlay.
And because of the recent postgres bump for 23.11, `ensureDBOwnership`
is the new way of dealing with DB permissions [1]. This means I had to
fix manually migrate my `gitea` DB and make it match the DB user.
[1]: https://github.com/NixOS/nixpkgs/pull/266270
Let's consolidate all modules under one path, so that NixOS,
home-manager, and nix-darwin (if I ever end up using it down the line)
would go under the same folder.