services: use doas if enabled

- Remove sudo from recurring-donations path because it's not used by
  the service

- Use doas instead of sudo in secure-node.nix

modules/operator.nix

@@ -22,7 +22,7 @@ in {
       default = [];
       description = "Extra groups.";
     };
-    sudoUsers = mkOption {
+    allowRunAsUsers = mkOption {
       type = with types; listOf str;
       default = [];
       description = "Users as which the operator is allowed to run commands.";
@@ -38,10 +38,14 @@ in {
       ] ++ cfg.groups;
     };
 
-    security.sudo.extraConfig = mkIf (cfg.sudoUsers != []) (let
-      users = builtins.concatStringsSep "," cfg.sudoUsers;
-    in ''
-      ${cfg.name} ALL=(${users}) NOPASSWD: ALL
-    '');
+    security = mkIf (cfg.allowRunAsUsers != []) {
+      # Use doas instead of sudo if enabled
+      doas.extraConfig = mkIf config.security.doas.enable ''
+        ${lib.concatMapStrings (user: "permit nopass ${cfg.name} as ${user}\n") cfg.allowRunAsUsers}
+      '';
+      sudo.extraConfig = mkIf (!config.security.doas.enable) ''
+        ${cfg.name} ALL=(${builtins.concatStringsSep "," cfg.allowRunAsUsers}) NOPASSWD: ALL
+      '';
+    };
   };
 }