Scheduler: Provide full meta-data for file-graph traversals

Since we potentially have a one-to-many mapping here, we simply use
the first `item` to provide the meta-data. This is a bit hacky, but
needs full SGraph development to be fixed "properly".

loki/bulk/scheduler.py

@@ -641,7 +641,11 @@ def process(self, transformation):
                         if not items:
                             continue
 
-                    transformation.apply(items[0].source, items=items)
+                    _item = items[0]
+                    transformation.apply(
+                        items[0].source, role=_item.role, mode=_item.mode,
+                        item=_item, items=items, targets=_item.targets,
+                    )
             else:
                 for item in traversal:
                     if item_filter and not isinstance(item, item_filter):