gitlab: Update requests query parameters

Increase number of origins per page to the maximum value allowed
by GitLab API (100) to send less requests.

Ask for simple responses to reduce size of JSON data.

swh/lister/gitlab/lister.py

@@ -159,6 +159,8 @@ class GitLabLister(Lister[GitLabListerState, PageResult]):
             "pagination": "keyset",
             "order_by": "id",
             "sort": "asc",
+            "simple": "true",
+            "per_page": "100",
         }
         if id_after is not None:
             parameters["id_after"] = str(id_after)