core: introduce the notion of provided features on components

Each component can optionally "provide" a feature, which is basically
a string that describes the feature (ex. "support.dbus"). If the
component loads successfully, the feature is marked as provided and
can be tested for its presence with wp_core_test_feature()

modules/module-lua-scripting/api/require.c

@@ -92,7 +92,7 @@ wp_require_api_transition_execute_step (WpTransition * transition, guint step)
             "libwireplumber-module-%s", api_name);
 
         self->pending_plugins++;
-        wp_core_load_component (core, module_name, "module", NULL, NULL,
+        wp_core_load_component (core, module_name, "module", NULL, NULL, NULL,
             (GAsyncReadyCallback) on_plugin_loaded, self);
       }
     }