fix: set correctly request->session

The session cookie was not created because request->session pointed at
a temporary session.

While here:
- do some cleaning in App
- set request->mount too
- add fcgi_cannot_create_request_delay to the config
- fix: in mailregister plugin get model_connector from env (and not from the request)

winixd/functions/functions.cpp

@@ -172,6 +172,7 @@ Error Functions::CheckSpecialFile(const Item & item)
 		system->mounts.ReadMounts(item.item_content.content_raw);
 		system->mounts.CalcCurMount(cur->request);
 		cur->mount = system->mounts.pmount;
+		cur->request->mount = cur->mount;
 		templates->ReadNewIndexTemplates();
 		templates->ReadNewChangeTemplates();