services: add role settings with explicit warning

lib/inventory/distributed-service/tests/per_instance_args.nix

@@ -137,6 +137,7 @@ in
               settings = { };
             };
           };
+          settings = { };
         };
         peer = {
           machines = {
@@ -146,6 +147,9 @@ in
               };
             };
           };
+          settings = {
+            timeout = "foo-peer";
+          };
         };
       };
       settings = {

lib/inventory/distributed-service/tests/per_machine_args.nix

@@ -102,18 +102,23 @@ in
       specificRoleSettings =
         res.importedModulesEvaluated.self-A.result.allMachines.jon.passthru.instances.instance_foo.roles.peer;
     };
-    expected = rec {
+    expected = {
       hasMachineSettings = true;
-      hasRoleSettings = false;
+      hasRoleSettings = true;
       specificMachineSettings = {
         timeout = "foo-peer-jon";
       };
       specificRoleSettings = {
         machines = {
           jon = {
-            settings = specificMachineSettings;
+            settings = {
+              timeout = "foo-peer-jon";
+            };
           };
         };
+        settings = {
+          timeout = "foo-peer";
+        };
       };
     };
   };