grafana: Support additional networks

roles/grafana/meta/argument_specs.yml

@@ -7,6 +7,14 @@ argument_specs:
         description: The domain grafana should be available on
         type: str
         required: true
+      grafana_additional_networks:
+        description: >-
+          A list of additional podman networks for the grafana container (in
+          addition to grafana network).
+        type: list
+        required: false
+        default: []
+        elements: str
 
       grafana_oauth_name:
         description: >-