Use sops for private key distribution

nixos/modules/borgbackup.nix

@@ -135,11 +135,7 @@ in {
       users.fsaccount.files = [
         {
           file = ".ssh/known_hosts";
-          parentDirectory = {
+          parentDirectory = {mode = "u=rwx,g=,o=";};
-            user = "fsaccount";
-            group = "users";
-            mode = "u=rwx,g=,o=";
-          };
         }
       ];
     };