flake.nix: Add app to locally build remote deployment

flake.nix

@@ -109,6 +109,18 @@
               )
               self.nixosConfigurations);
 
+            deploy-local = lib.recurseIntoAttrs (lib.mapAttrs
+              (hostname: machine: pkgs.writeShellScript "deploy-local-${hostname}" ''
+                ${pkgs.nixos-rebuild.override { nix = pkgs.nixFlakes; }}/bin/nixos-rebuild \
+                    switch \
+                    --flake .#${hostname} \
+                    -L \
+                    --build-host localhost \
+                    --target-host root@${machine.config.deployment.targetHost} \
+                    --use-substitutes
+              '')
+              self.nixosConfigurations);
+
             unlock = lib.recurseIntoAttrs (lib.mapAttrs
               (hostname: machine:
                 let