feat(modules): move nix settings to a seperate module

machines/raspite/configuration.nix

@@ -4,6 +4,9 @@
   imports = [
     ./hass.nix
   ];
+
+  commonSettings.nix.enableMirrors = true;
+
   nixpkgs.overlays = [
     # Workaround https://github.com/NixOS/nixpkgs/issues/126755#issuecomment-869149243
     (final: super: {
@@ -18,13 +21,6 @@
     raspberrypi-eeprom
   ];
 
-  # Use mirror for binary cache
-  nix.settings.substituters = [
-    "https://mirrors.bfsu.edu.cn/nix-channels/store"
-    "https://mirrors.ustc.edu.cn/nix-channels/store"
-  ];
-  nix.settings.experimental-features = [ "nix-command" "flakes" ];
-
   system.stateVersion = "24.05";
   
   networking = {
@@ -51,10 +47,6 @@
     wheelNeedsPassword = false;
   };
 
-  nix.settings = {
-    trusted-users = [ "@wheel" ];
-  };
-
   # fileSystems."/".fsType = lib.mkForce "btrfs";
   boot.supportedFilesystems.zfs = lib.mkForce false;