Add jslint check to PR CI tests
For now, from all possible lint checks, pylint applies only.
jslint can prevent JavaScript errors at WebUI.
Fixes: https://pagure.io/freeipa/issue/7717
Fixes: https://pagure.io/freeipa/issue/7718
Reviewed-By: Christian Heimes <cheimes@redhat.com>
Reviewed-By: Christian Heimes <cheimes@redhat.com>