After trigger creation we should tell the user to which hosts it applies based on items / temlpates. Currently, there's only one message "trigger added", which can be somehow confusing if the trigger is not effective for current host / template (user will not see it in trigger table).

Instead, we should show something like "Trigger added, affecting hosts host1, host2, templates template1, template2" (or "Trigger added, affecting 25 hosts and 28 templates" for large deployments).