Introduce nix-homebrew plus homebrew-core, homebrew-cask, and homebrew-bundle repositories. Also, enable nix-homebrew.darwinModules.nix-homebrew for the NixOS system configuration.
This commit includes the atticd service to the sgx-nixos system. The `atticd.nix` file has been added with default configuration and the attic service has been included in imports in `default.nix`. Modifications were made in `flake.nix` and `flake.lock` to integrate attic dependencies.
Harald Hoyer